Category Archives: exercise

Heart Rate Recovery: A Simple and Powerful Predictor of Mortality Now Available On Your Apple Watch

Apple Watch and other fitness trackers have the capability to provide us with information on cardiovascular parameters which reflect the activity of the autonomic nervous system (ANS). Measures of the activity of the ANS reflect the balance between the sympathetic nervous system (which activates fight and flight responses) and the parasympathetic nervous system (which activates “rest and digest” activities) and have been shown to be powerful predictors of mortality.

Most of the attention in this areas has been on heart rate variability (HRV) with various wearables trying to promote HRV as a surrogate marker for stress. The OURA ring people for example state without evidence that “high heart rate variability is an indication of especially cardiovascular, but also overall health as well as general fitness.”

Although unimpressed with the HRV data from Apple Watch or the OURA ring I have recently discovered that I can get a more useful parameter of ANS tone from my Apple Watch-Heart Rate Recovery.

What Is Heart Rate Recovery?

Heart Rate Recovery (HRR) is the rate of decline in heart rate after the cessation of exercise. Basically you measure heart rate right when you stop exercising and again a minute later (and/or two minutes later) and subtract one from the other.

Unlike HRV you don’t really need any high tech devices to make this simple but highly reproducible measurement. You can simply measure your pulse the old-fashioned way by putting a finger on your carotid or radial artery and counting the beats.

What happens to the heart rate during exercise has long been considered to be due to the combination of parasympathetic withdrawal and sympathetic activation.

The fall in heart rate immediately after exercise has been shown to be a function of the reactivation of the parasympathetic nervous system. It is accelerated in athletes and blunted in patients with heart failure.

Heart Rate Recovery As A Predictor Of Mortality

A 1999 study published in the New England Journal of Medicine found that abnormally low HRR doubled the risk of dying over 6 years.

The study examined outcomes in 2428 consecutive adults (mean age 57 years, 63 percent men) without significant prior cardiac disease who were referred to the Cleveland clinic cardiac lab for nuclear stress testing.  Patients underwent symptom-limited exercise on a treadmill using a standard or modified Bruce protocol.

Heart rate was recorded at peak exercise and then patients walked upright and were walking at a speed of 1.5 miles per hour at a grade of 2.5 percent when heart rate was checked a minute later.

Median HRR was 17 beats per minute, with a range from the 25th to the 75th percentile of 12 to 23 beats per minute. Abnormally low HRR was selected as <13 beats/min and was found in 639 patients (26 percent).

In univariate analyses, a low value for the recovery of heart rate was strongly predictive of death, conferring a four-fold increased risk. After adjustment for multiple confounding factors including age and exercise capacity, patients with HRR <13 beats/min had a two-fold risk of dying.

This 20 year old study and HRR remain highly relevant. The paper has been cited 1001 times since publication and thus far in 2019 58 papers have referenced it.

In a follow up study this same Cleveland Clinic group looked at nearly 10 thousand patients undergoing treadmill ECG testing and found HRR <13 beats/min doubled the 5 year risk of death. In the figure below mortality jumps markedly as HRR drops below 13 and quite dramatically if <10 beats/min.

m_joc00680f2

 

 

 

 

 

Subsequent studies from different investigators confirmed that HRR is associated with mortality, independent of workload and myocardial perfusion defects, treadmill risk score, and even after adjusting for left ventricular function and angiographic severity of coronary disease.

There has been a lack of consistency in these studies in stress protocols, activity post-exercise and optimal duration of heart beat measurement post exercise.

This 2001 JACC paper determined that a 2 minute HRR <22 beats/min provided a better cut-point than one minue HRR <13 beats/min in predicting mortality at 7 years in male veterans. Individuals underwent maximal treadmill followed by lying down and those with an abnormal HRR were 2.6 times more likely to die. The HRR was equivalent to age and exercise capacity for predicting death.

Apple Watch and Heart Rate Recovery

It’s not entirely obvious how to view the heart rate recovery data on your Apple Watch but it is routinely logged if you record an activity and end it precisely at the end of the activity.  To see it you must leave the activity app and open the Heart Rate APP.

Scroll to the bottom of the screen and you will see HR data on your most recent activity including the peak HR and one minute recovery heart rate.

Click on that tab and the full and awe-inspiring graph of your recovery heart rate over 3 minutes is revealed. Here is mine which followed a 1.5 mile run at 6-7 MPH. I did not walk at 1.5 MPH on a 2.5% grade in recovery which would be needed if one wanted to more carefully compare a personal HRR to the numbers from the 1999 NEJM study.

My data shows a peak HR of 121 BPM which dropped to 90 BPM at one minute (121-90=31). Two minute recovery is 121-78 or 43 bpm. Both values are WNL

 

IMG_2A2C306430A7-1

The Watch only stores data on your last workout but if you go to the Activity app on your iPhone (something I had never previously done)  you will find under the workouts tab a complete listing of all previous workouts.

 

 

 

 

Click on the workout of interest and all the data from the workout is wondrously revealed including cadence, pace and  near the bottom heart rate changes. Swipe the heart rate changes during exercise to the left and the heart rate recovery graph is revealed. This time you will have to do the subtraction for yourself

Heart Rate Recovery-Simple, Powerful And Intuitive Measure of Autonomic Tone

So there you have it. Heart Rate Recovery (unlike HRV) is a simple parameter, easy to understand and measure. It yields information on your vagal/parasympathetic tone and has been proven to be a powerful and independent predictor of your overall mortality.

It makes more sense to pay attention to HRR if one wants a measure of your body’s autonomic tone than HRV.

If your one minute HRR is <13 beats per minute or two minute HRR <22 beats per minute this is a bad prognostic sign. If you have not been diagnosed with significant cardiovascular disease consider seeing a physician for evaluation..

For those who have been sedentary and are deconditioned or overweight, consider an abnormal HRR as a wake-up call to modify your lifestyle and improve your mortality.

For  healthy, asymptomatic individuals the HRR can serve as a marker for your overall cardiovascular fitness. Monitor it along with your exercise capacity, peak heart rate and resting heart rate to raise your awareness of how your exercise is influencing your overall autonomic nervous system balance.

Autonomously Yours,

-ACP

Are You Doing Enough Push Ups To Save Your Life?

The skeptical cardiologist has always had a fondness for push-ups. Therefore I read with interest a recent study published in JAMAOpen which looked at how many push-ups a group of 30 and 40-something male firefighters from Indiana could do and how that related to cardiovascular outcomes over the next ten years.

The article was published in the peer-reviewed journal JAMA Network Open, and is freely available to access online.

The British National Health Service pointed out that “The UK media has rather over exaggerated these findings:”

Both the Metro and the Daily Mirror highlighted the result of 40 push-ups being “the magic number” for preventing heart disease, but in fact being able to do 10 or more push-ups was also associated with lower heart disease risk.

What Was Studied?

The study involved 1,104 male firefighters (average age 39.6) from 10 fire departments in Indiana who underwent regular medical checks between 2000 and 2010. 

At baseline the participants underwent a physical fitness assessment which included push-up capacity (hereafter referred to as the push-up number (PUN))and treadmill exercise tolerance tests conducted per standardized protocols.

For push-ups, the firefighter was instructed to begin push-ups in time with a metronome set at 80 beats per minute. Clinic staff counted the number of push-ups completed until the participant reached 80, missed 3 or more beats of the metronome, or stopped owing to exhaustion or other symptoms (dizziness, lightheadedness, chest pain, or shortness of breath). Numbers of push-ups were arbitrarily divided into 5 categories in increments of 10 push-ups for each category. Exercise tolerance tests were performed on a treadmill using a modified Bruce protocol until participants reached at least 85% of their maximal predicted heart rates, requested early termination, or experienced a clinical indication for early termination according to the American College of Sports Medicine Guidelines (maximum oxygen consumption [V̇ O2max]).

The main outcomes assessed were new diagnoses of heart disease from enrollment up to 2010. 

Cardiovascular events were verified by periodic examinations at the same clinic or by clinically verified return-to-work forms. Cardiovascular disease–related events (CVD) were defined as incident diagnosis of coronary artery disease or other major CVD event (eg, heart failure, sudden cardiac death)

Here’s the graph of the probability of being free of a CVD event on the y-axis with time on x-axis.

The black line represents those 75 firefighters who couldn’t make it into double digits, the green those 155 who did more than 40 pushups.

Participants able to complete more than 40 push-ups had a significant 96% lower rate of CVD events compared with those completing fewer than 10 push-ups.

It is surprising that the push up number seemed a better predictor of outcomes than the exercise test, This should be taken with a grain of salt because although the investigators report out “VO2 max” the stress tests were not maximal tests.

The firefighters with lower push up numbers were fatter, more likely to smoke and had higher blood pressure, glucose and cholesterol levels.

What useful information can one take from this study?

You definitely cannot say that being able to do more than 40 pushups will somehow prevent heart disease. The PUN is neither causing nor preventing anything.

The PUN is a marker for the overall physical shape of these firefighters. It’s a marker for how these men were taking care of themselves. If you are a 39 year old fireman from Indiana and can’t do 11 push-ups you are in very sorry condition and it is likely evident in numerous other ways.

The <11 PUN crew were a bunch of fat, diabetic, insulin resistant, hyperlipidemic, out-of-shape hypertensives who were heart attacks in the waiting.

Push-ups Are A Great Exercise

Despite the meaningless of this study you should consider adding push-ups to your exercise routine. Doing them won’t save your life but it will contribute to mitigating the weakness and frailty of aging. Don’t obsess about your PUN.

I’ve always liked push-ups and highly recommend them. They require no special equipment or preparation. It’s a quick exercise that builds upper body muscle strength, adds to my core strength and gets my heart rate up a bit. For some reason my office in O’Fallon is always cold so several times during the day when I’m there I’ll do 100 jumping jacks and drop on the carpet and do some push-ups in an effort to get warm.

I don’t do them every day but the last time I tried I could do 50 in less than a minute and that has me convinced I will live forever!

Calisthenically Yours,

-ACP

N.B. In my post on mitigating sarcopenia in the elderly I talked about the importance of resistance exercise:

Americans spend billions on useless supplements and vitamins in their search for better health but exercise is a superior drug, being free  and without drug-related side effects

I’ve spent a lot of time on this blog emphasizing the importance of aerobic exercise for cardiovascular health but I also am a believer in strength and flexibility training for overall health and longevity.

As we age we suffer more and more from sarcopenia-a gradual decrease in muscle mass.

Scientific reviews note that loss of muscle mass and muscle strengh is quite common in individuals over age 65 and is associated with increased dependence, frailty and mortality

Push-ups are a great resistance exercise. For a description of the perfect form for a push up see here.

Which Exercise Is Best For Heart Health: Swimming or Walking?

Reader Pat asked the skeptical cardiologist the following question:

Which would be the better heart healthy choice? Walking briskly 3 x week or swimming for 45 minutes 2-3 x a week?

Swimming is an attractive alternative to walking or running for many of my patients with arthritis because it is a lot easier on the load-bearing joints of the lower extremities.

To my surprise there is at least one study (from Australia) comparing swimming and walking that was published in the journal Metabolism in 2010.

The investigators randomly assigned 116 sedentary women aged 50-70 years to swimming or walking. Participants completed 3 sessions per week of moderate-intensity exercise under supervision for 6 months then unsupervised for 6 months.

Compared with walking, swimming improved body weight, body fat distribution and insulin resistance in the short term (6 months).

At 12 months swimmers had lost 1.1 kg more than walkers and had lower bad cholesterol levels.

It should be noted that these differences barely reached significance .

Types of Activities And The Intensity of Exercise

My general recommendations on exercise (see here) give examples of different aerobic physical activities and intensities.

These activities are considered Moderate Intensity

  • Walking briskly (3 miles per hour or faster, but not race-walking)
  • Water aerobics
  • Bicycling slower than 10 miles per hour
  • Tennis (doubles)
  • Ballroom dancing
  • General gardening Vigorous Intensity

These types of exercise are considered Vigorous Exercise

  • Racewalking, jogging, or running
  • Swimming laps
  • Tennis (singles)
  • Aerobic dancing
  • Bicycling 10 miles per hour or faster
  • Jumping rope
  • Heavy gardening (continuous digging or hoeing, with heart rate increases)
  • Hiking uphill or with a heavy backpack

As a rule of thumb, consider 1 minute of vigorous exercise equivalent to 2 minutes of moderate exercise and shoot for 150 minutes per week of moderate exercise or 75 minutes of vigorous exercise.

Of course one can swim laps at peak intensity or at a very slow, leisurely pace so swimming laps doesn’t always qualify as “vigorous” exercise. Likewise one can play singles tennis languorously and be at a moderate or lower intensity of exercise.

It is entirely possible that the swimmers were working at a higher intensity during their sessions than the walkers and that could be the explanation for the differences seen between the two groups.

Ultimately, the best type of  exercise for heart health is the one you can do and  (hopefully) enjoy on a regular basis.

Antilanguorously Yours,

-ACP

N.B. Speaking of swimming. A year ago I wrote about longevity and featured Eugene, a 98 year old who could swim the length of a swimming pool underwater. Eugene turns 100 in 2 days.

Mitigating Sarcopenia In The Elderly: Resistance Training Is A Powerful Potion

While researching afib-detection apps recently, the skeptical cardiologist stumbled across an article with the title “Resistance training – an underutilized drug available in everybody’s medicine cabinet”

This brief post from the British Journal of Sports Medicine blog nicely presents the rationale for using strength training to improve the overall health of the elderly. I have reblogged it below.

Americans spend billions on useless supplements and vitamins in their search for better health but exercise is a superior drug, being free  and without drug-related side effects

I’ve spent a lot of time on this blog emphasizing the importance of aerobic exercise for cardiovascular health but I also am a believer in strength and flexibility training for overall health and longevity.

As we age we suffer more and more from sarcopenia-a gradual decrease in muscle mass.

Scientific reviews note that loss of muscle mass and muscle strengh is quite common in individuals over age 65 and is associated with increased dependence, frailty and mortality

Specific information on progressive resistance training for the elderly is sparse but I found this amusing and helpful video on a Canadian site that provides some guidance for beginners.

 

And below is the referenced blog post:

Resistance training – an underutilised drug available in everybody’s medicine cabinet

By Dr Yorgi Mavros @dryorgimavros

As we get older we begin to lose muscle mass, approximately 1% every year. But more importantly, the decline in muscle strength declines at a rate 3-times greater [1]. The consequences of this decline in strength are significant, with lower muscle strength being associated with an increased risk dementia[2], needing care, and mortality[3]. But should we accept this as our fate, or is there anything we can do prevent, reverse or at least slow this age-related decline?

In 1990, a type of exercise called progressive resistance training, commonly known as strength training, was introduced to 9 nonagenerians living in a nursing home, specifically to treat the loss of muscle mass and strength, and the functional consequences of disability [4]. After just 8 weeks, these older adults saw average strength gains of 174%, with 2 individuals no longer needing a cane to walk. In addition, one out of the three individuals who could not stand from a chair, was now able to stand up independently. Just take a moment to think about the results of that study. If I told you there was a medicine that you or a loved one could take, and it could make either of you strong enough to now get out of a chair, would you take it?

What if you or a loved one had a hip fracture, and I told you that same medicine could help reduce the risk of mortality by 81%, and the risk of going in to a nursing home by 84%, as was shown in this study [5]. Currently, the only way to take this medicine is by lifting weights, or pushing against resistance.

A recent study from Britain, [6] showed an association between adults who participated in 2 days per week of strength training and a 20% reduction in mortality from any cause, and a 43% reduction in cancer mortality. Data from the Women’s Health Study in the US published at a similar time were very similar, with women reporting up to 145 minutes per week of strength training having a 19-27% reduced risk of mortality  from any cause [7].

So where does the benefit of strength training come from? First and foremost, it is anabolic in nature (meaning that it can stimulate muscle growth) making it the only type of exercise that can address the age-associated decline in muscle mass and strength. Within our laboratory at the University of Sydney, we have shown that we can use this type of exercise to improve cognitive function in adults who have subjective complaints about their memory [8]. What’s important though, is that there was a direct relationship between strength gains and improvements in cognition, and so maximizing strength gains should be a key focus if you want to maximize your benefit [9]. This type of exercise has even been taken into hospitals and used in adults with kidney failure undergoing haemodialysis, where it was shown to reduce inflammation, and improve muscle strength and body composition [10].

Other laboratories around the world have also used strength training to increase bone strength in postmenopausal women [11], help manage blood sugar levels in adults with type 2 diabetes [12], as well as to counteract the catabolic side effects of androgen-deprivation therapy for men with prostate cancer [13]. Not to mention its benefits to sleep [14], depression  [15] and recovery from a heart attack  [16].

So it is no surprise to see that the  Australian [17] and UK [18] public health guidelines for physical activity recommend we take part in activities such as strength training 2-to-3 days per week. Unfortunately however, these recommendations lack detail and guidance on intensity and frequency.

A key theme in all the randomized controlled studies discussed above, is that not only were exercises performed at least 2 days per week, but they were fully supervised, used machine and/or free weights, and were done at a high intensity, which is commonly set to 80% of an individual’s peak strength. It is for this reason I like to focus on the guidelines put forward by The American College of Sports Medicine (ACSM) [19]. The ACSM advises that everyone, including older adults do at least 2 days of progressive resistance training, which is to be performed at a moderate (5 – 6) to high/hard (7 – 8) intensity on a scale of 0 to 10, involving the major muscle groups of the body. So if you are looking to maximise the benefit from your time in the gym, or looking to make a positive change to your lifestyle, remember that there is medicine you can take; Try lifting some weights or doing other forms of strength training, 3 days a week, and importantly, make sure it feels moderate to hard. Not only will it add years to your life, but life to your years.


Since college I have regularly done weight training 3 times per week As I get  dangerously close to age 65 and joining the ranks of the “elderly” I have ramped up the intensity of my workouts, working hard to forestall the sarcopenia that will ultimately be my fate.

Antisarcopenically Yours,

-ACP

***************************

Video credit: Produced for the University of British Columbia’s (UBC) Department of Physical Therapy, the Aging, Mobility, and Cognitive Neuroscience Laboratory, the Centre for Hip Health and Mobility and the Brain Research Centre at Vancouver Coastal Health and UBC
hiphealth.ca/news/preventing-dementia

 

What Should Your Maximal Exercise Heart Rate Be?: The Importance Of Using The Right Age-Predicted HRmax Formula

A reader who runs 5Ks posted a question recently which indicated concern that his heart rate during intense exercise was much higher than his age-predicted heart rate.  He writes

I’m 65, exhaustion HRmax is 188, HRave for 5k is usually 152-154 and interval HRmax is usually 175-179 depending on how hard I push”

He wondered if he should be concerned about being a “high-beater.”

This prompted the skeptical cardiologist to examine the literature on age-predicted maximal heart rate which led to the shocking discovery that the wrong formula is being utilized by most exercise trainers and hospitals.

First , some background.

The peak heart rate achieved with maximal exertion or HRmax has long been known to decline with aging for reasons that are unclear.

The HR achieved with exercise divided by the HRmax x 100 (percentage HRmax) is widely used in clinical medicine and physiology as a basis for prescribing exercise intensity in cardiac rehab programs, disease prevention programs and fitness clinics.

During stress tests we seek to have patients exercise at least until  their heart rate gets to at 85% of HRmax.

The Traditional Formula For HRmax

The formula that is widely used for HRmax is

HRmax = 220-age

It appears to have originated from flawed studies in the early 1970s. These studies included subjects with cardiovascular disease, smokers and patients on cardiac medications.

The Improved HRmax Formula

Tanaka, et al in 2001 performed a meta-analysis of previous data on HRmax along with accumulating data in their own lab. This was the first study to examine healthy, unmedicated, nonsmokers. In addition each subject achieved a verified maximal level of effort as documented by metabolic stress testing.

Their analysis obtained the regression equation (which I term the Tanaka equation)

HRmax = 208-(0.7 x age) 

Below is the graph of the laboratory measurements from which the regression equation was obtained.

Relation between maximal heart rate (HRmax) and age obtained from the prospective, laboratory-based study.(Tanaka, et al)

This graph shows how  inaccurate the traditional equation is, especially in older  individuals like my reader:

Regression lines depicting the relation between maximal heart rate (HRmax) and age obtained from the results derived from our equation (208 − 0.7 × age) (solid linewith 95% confidence interval), as compared with the results derived from the traditional 220 − age equation (dashed line). Maximal heart rates predicted by traditional and current equations, as well as the differences between the two equations, are shown in the table format at the top.(from Tanaka, et al)

The traditional equation in comparison to the Tanaka equation  overestimates HRmaxin young adults, intersects with the present equation at age 40 years and then increasingly underestimates HRmaxwith further increases in age. For example, at age 70 years, the difference between the two equations is ∼10 beats/min. Considering the wide range of individual subject values around the regression line for HRmax(SD ∼10 beats/min), the underestimation of HRmaxcould be >20 beats/min for some older adults.

There are likely lots of perfectly healthy individuals in their sixties and seventies then who have heart rates at maximal exertion that exceed by 10 to 20 beats per minute the HR max predicted by the traditional formula.

This is due to a combination of the inaccuracy of the traditional formula and the wide variation in normal HR max at any given age (standard deviation (SD) of approximately 10 beats/min.)

Thus, my reader at age 65 would have a HRmax predicted by the Tanaka equation as

208-0.7 x 65=162

If we allow for a 10 BPM range of normality above and below 162 BPM we reach 172 BPM which gets close to  but doesn’t reach the reader’s 188 BPM.

If you examine the scatterplot of the Tanaka data you can see that several of the points for age 65 reach into the 180s so chances are my reader is still within normal limits

The Bottom Line on HRmax

The widely used traditional formula for predicting HR max is inaccurate.

Athletes, trainers, physicians and hospitals should switch to using the superior Tanaka HR max formula.

Individuals should keep in mind that there is a wide range of HR response to exercise in normals and variations of 10 BPM above and below the predicted response are common and of no concern.

Chronotropically Yours

-ACP

Addendum. The 220-age formula is so heavily etched into my brain that I used 220 instead of 208 when I initially calculated the predicted max HR for my reader. this has been corrected.Thanks to Chris Sivewright for pointing this out.

Exercise As Medicine: Preventing Age-Related Decline in Cardiac Stiffness

As we age our hearts and arteries become stiffer. This cardiovascular stiffening plays a key role in hypertension, atrial fibrillation, and heart failure in older individuals (1).

Age-related cardiac stiffening is worse in those who are sedentary compared to those who exercise regularly (2).

Recent studies strongly suggest that regular exercise can prevent or minimize these age-related changes, thereby hopefully reducing the high rate of heart failure, hypertension and atrial fibrillation in the elderly.

In my post on fitness as a vital sign I briefly mentioned a fascinating study from 2014 which looked at 102 healthy seniors (age>64 years) and stratified them into 1 of 4 groups based on their lifelong histories of endurance exercise training.

Consider which of these 4 categories you fall into:

Sedentary subject-exercised no more than once per week during the prior 25 years.

Casual exercisers-engaged in 2-3 sessions per week

Committed exercisers-performed 4-5 sessions per week

Competitive “Masters level” athletes-trained 6-7 times per week

Exercise sessions were defined as periods of “dynamic activity lasting at least 30 minutes.”

The participants had sophisticated measures of their exercise capacity (max VO2), the size and mass of their left ventricles (cardiac MRI) and the stiffness of their left ventricles (invasive pressure/volume curves to calculate LV compliance and distensibility.)

This graph shows the key finding of the study: a markedly different pressure/volume curve in the sedentary and casual exercisers (blue and red dots) versus the committed or master exercisers. The two curves on the left correspond to a very stiff heart, similar to curves found in patients with heart failure.

The far right curve of competitive exercisers resembles that of a young heart.

The black triangle curve of the committed exerciser is in between these extremes

F5.large-3

The study concludes:

“low doses of casual, lifelong exercise do not prevent the decreased compliance and distensibility observed with healthy, sedentary aging. In contrast, 4 to 5 exercise sessions/week throughout adulthood prevent most of these age-related changes”

It would appear we need at least 4-5 30 minute exercise session per week to forestall the age-related stiffening of the heart and lower our chances of getting heart failure, hypertension and atrial fibrillation.

Since this was an observational study there is always a chance that lack of exercise is not the causes of poor cardiac stiffness.  It is conceivable that those of us with stiffer hearts tend to be more sedentary because of the poor cardiac function.

Can You Reverse The Age-Related Changes In Cardiac Stiffness?

If you have already reached middle age there is still hope for you as these same investigators recently published a study showing that cardiac stiffness can be improved with exercise. These findings imply that lack of exercise is the cause of worsening cardiac stiffness with aging.

This study identified 61 sedentary men in their mid-fifties and randomly assigned them to either 2 years of exercise training or attention control (a combination of yoga, balance, and strength training 3 times per week for 2 years) and measured their LV stiffness and max VO2 before and after intervention.

Max VO2 increased by 18% and LV stiffness declined from .072 to .051 in the exercise group but did not change in the control group.

The exercise training arm of this study involved a mixture of continuous moderate-intensity aerobic exercise combined with high intensity training. The high intensity portion of the program involved exercising at 90-95% of HR maximum for 4 minutes followed by a 3 minute active recovery period, repeated 4 times.

Over a period of 6 months under the guidance of exercise physiologists the participants had their exercise levels gradually increased. After 6 months they were training 5-6 hours per week, including 2 of the “high intensity interval” session and 1 long (>/= 1 hour) and one 30-minute base pace session each week.

By the sixth month, participants were training 5 to 6 hours per week, including 2 interval sessions, and 1 long (at least an hour) and one 30-minute base pace session each week.

How Much Exercise Do We Need To Minimize Cardiac Aging?

This chart from recent European guidelines on lifestyle for prevention of disease describes different intensities of aerobic exercise:

 

screen-shot-2016-10-01-at-10-18-34-am

 

 

 

 

 

These guidelines suggest that if you engage in vigorous exercise such as running or jogging, cycling fast or singles tennis, you only need to achieve 75 minutes per week. Moderate exercise such as walking or elliptical work-outs requires at least  150 minutes/week.

Based on these recent studies on exercise and cardiac stiffness and the bulk of scientific literature on the overall health benefits of exercise I would advise for all individuals with or without heart disease

-If you are sedentary, become a committed exerciser.

-Committed exercise means some form of dynamic exercise 4-5 times per week

-If you are already a committed exerciser at moderate intensity levels consider adding to your routine one or two sessions of high intensity interval exercise.

-High intensity exercise will require you to get your heart rate up to 90-95% of your maximum 

-Predicted maximal HR=220 -age.  For a 60 year old this equals 160 BPM. 90% of 160 equals 144 BPM. 

Compliantly Yours,

-ACP

 

 

 

 

Urban Cycling, Part 2: Hit and Run Drivers and Bike Helmets

A doctor colleague of the skeptical cardiologist was riding his bike on a quiet road here in St. Louis recently when he suddenly awoke in a hospital bed. His friend who was riding in front of him heard a crash, turned and saw a black car making a U-turn and speeding off. Fortunately, the good doctor, suffered only the concussion and multiple bruised ribs and will live to ride again

He is in his seventies and I asked him if he would, indeed, climb onto the saddle of a two-wheeled vehicle in the future and he indicated yes, but never again on roads shared with cars.

I also inquired as to the state of his bike helmet post-trauma: it was shattered into multiple pieces.

In a previous post I pondered the question: Does cycling to work make you more or less likely to die?

cycling to work for many individuals would provide the daily physical activity that is recommended for cardiovascular benefits. However, cycling in general, and urban cycling in particular, carries a significant risk of trauma and death from accidents and possibly greater exposure to urban pollutants.

In the Netherlands cycling to work likely makes you less likely to die.

One study quantified the impact on all-cause mortality if 500,000  people made a  transition from car to bicycle for short trips on a daily basis in the Netherlands and concluded

For individuals who shift from car to bicycle, we estimated that beneficial effects of increased physical activity are substantially larger (3–14 months gained) than the potential mortality effect of increased inhaled air pollution doses (0.8–40 days lost) and the increase in traffic accidents (5–9 days lost). Societal benefits are even larger because of a modest reduction in air pollution and greenhouse gas emissions and traffic accidents.

In St. Louis, however, I suspect my longevity would be substantially reduced by cycling the 15 miles of heavily trafficked roads from University City to St. Lukes Hospital in Chesterfield. I would be cheek to jowl with SUVs, pick-up trucks, and mini-vans full of distracted, texting and chatting commuters.

Should  Bike Helmets Be Mandated?

Like most people I know, my colleague wears a bike helmet religiously when cycling. He, like many who have shared their bike accident stories with me, believes the bike helmet saved his life. I certainly can’t refute that possibility but it is impossible to know with certainty.

I’ve posted my analysis of the wisdom of mandating bike helmets here and even after hearing the good doctor’s story,  I still refuse to wear one.

Typical skeptical cardiologist bike riding garb. No helmet but safari (not bee-keeper) hat because sun is not his facial friend.

A commonly cited statistic is that bike helmets reduce serious head injuries by 85% and brain injuries by 88%.  This comes from an observational  study  published in 1989 which has serious limitations and has never been reproduced. For an exhaustive critique of these data see here.

I think a fair summary is in this British Medical Journal editorial which is behind a paywall but can be reviewed as a PDF here (bmj-june-2013.pdfbicycle helmets and the law).

 

Larry Husten, a journalist, who writes an excellent cardiology blog at cardiobrief.org apparently agrees with me and has recently written about “The Unintended Consequences of Bike Helmets.”

I encourage everyone to read his post which can be found here.

Here is his main point:

I am opposed to public health campaigns that focus on helmets, thereby implanting in people’s minds the dangers of cycling. Instead, in my view, the public health agenda regarding cycling should be to promote the far greater health benefits of cycling. The overarching goal of any public health campaign should be to dramatically increase cycling in the US, thereby encouraging physical activity and helping to reduce obesity and diabetes.  In tiny Denmark, by way of example, one expert, Lars Bo Andersen, PhD, of Western Copenhagen University of Applied Sciences, reports that “26 persons were killed in the whole country in cycle accidents last year, but more than 6000 deaths were avoided due to the huge amount of physical activity this behavior is a result of.”

Circuitously Yours,

-ACP

Speaking of Holland, the skeptical cardiologist will be visiting this hotbed of cycling, tulips and dikes in July.

I’ll be staying in Haarlem but wandering around the country researching cycling, assisted suicide and the Dutch dairy industry which may be responsible for the Dutch having gone from being among the shortest people in Europe to being the tallest in the world.

Nonskeptical Musical Thoughts On Dick Dale and the Dead While Running For Longevity

Since determining that running would lower my cardiovascular risk and that it was actually good for my wonky knees (running is associated with a lower risk of ostearthritis or hip replacement, see here), I’ve been trying to do it regularly.

It has become therapeutic in many ways, aiding sleep and reducing stress levels. And, unlike my bike riding adventures, I have yet to fall and injure myself running and I don’t get dirty looks for not wearing a helmet.

I’ve even contemplated running 5 kilometers,  although not as part of any formal exhibition: just a personal , private goal. To this end I have for the first time recently run 4 kilometers.

Listening to music during these longer runs greatly helps the time pass and sometimes I am able to find songs which fit my running cadence, albeit not through any systematic analysis but through mere serendipity. I let my entire musical collection (nicely streamed by Apple music) be my running playlist and this ranges from the Talking Heads to Thelonius Monk to Bach.

This morning’s run (the second time I reached 4K) I was aided by two songs: one by the king of surf guitar, the other by the kings of psychedelic jam rock.

Dick Dale and Miserlou

Although, Dick Dale was huge in the early sixties, he did not register on my musical radar until  I watched Pulp Fiction and in its dazzling opening scene and  was jolted by Dale’s staccato machine gun guitar riffs alternating with his plaintive trumpet solo on  “Miserlou“.

I immediately strapped on my Strat and began trying to emulate his unique playing style.

Here’s Dick and the Del-Tones performing their version for the movie “A Swinging’ Affair”

This version contains none of the rhythmic power and electrifying guitar attack of the single and the band appears to be on tranquilizers. To make matters worse, Dick  doesn’t play that magical melodic moaning trumpet solo which contrasts so brilliantly with the pile-driving reverb-drenched guitar riffs on the original version.

You can see some of the power of the left-handed Dale in this live performance of Miserlou from 1995 but alas, no trumpet solo.

Dick Dale, remarkably, is still touring and playing well at age 80.

As fortune would have it the beats per
minute of this song is 173 which fits my preferred running speed stride cadence perfectly.

The Other One (Not Cryptical Envelopment)

The next song to aid me on my run was a live performance from the Grateful Dead’s 1972 European Tour  which is 36 minutes long.

I was slow to revere the Dead but when I first listened to their live album Europe ’72 I was hooked. Instead of studying in college, I spent way too many hours playing Sugar Magnolia (and Blue Sky, et al..)  thereafter.

The Other One highlights their free and wild improvisational style. While running I could focus on what Keith Godchaux was doing on the piano and that takes me to a psychic place in which I feel no pain.

Please excuse my hubris but I am convinced that I could have done a good job as the Dead keyboardist.  It’s probably a good thing I never got that gig, however, as it carries a very high mortality rate (not to mention that I’m a much better cardiologist than keyboardist.)

As Billboard pointed out in its obituary on the last keyboardist, Vince Welnick (who committed suicide by slitting his throat at age 55 in 2006):

Welnick was the last in a long line of Grateful Dead keyboardists, several of whom died prematurely, leading some of the group’s fans to conclude that the position came with a curse.

Welnick had replaced Brent Mydland, who died of a drug overdose in 1990. Mydland succeeded Keith Godchaux, who died in a car crash shortly after leaving the band. And Godchaux had replaced the band’s original keyboard player, Ron “Pigpen” McKernan, who died at 27 in 1973.

Last week a very good Grateful Dead documentary (Long Strange Trip) was released on Netflix. I’ve been somewhat mesmerized by what I’ve watched so far.  For example, at one point, Phil Lesh reveals that Jerry Garcia asked him to join the band as their bassist even though he had never played the instrument. (If only he had asked me!)

Strangetrippingly Yours

-ACP

N.B. Miserlou is a very old folk song with a scale that sounds exotic to Western ears: the double harmonic scale

per Wikipedia

The song’s oriental melody has been so popular for so long that many people, from Morocco to Iraq, claim it to be a folk song from their own country. In fact, in the realm of Middle Eastern music, the song is a very simplistic one, since it is little more than going up and down the Hijaz Kar or double harmonic scale (E-F-G#-A-B-C-D#). It still remains a well known Greek, Klezmer, and Arab folk song.

 

 

 

Longevity: Lifespan, Healthspan and Swimming Underwater At Age 98

img_7056
Eugene and Naomi.

The skeptical cardiologist has a few nonagenarian patients who seemingly defy the ravages of aging and remain vibrant and active into their late 90’s.

Eugene, for example, still ballroom
dances regularly with his wife, Naomi and swims underwater significant distances.

In this video, recorded when he was 97, you can see him swim the length of a swimming pool underwater

As life expectancy at birth has increased  from 35 years in 1900 to over 80 years now, we see more and more individuals reaching their nineties. Ongoing research seeks to further extend our lifespan.

But just as important as increasing lifespan is increasing healthspan, the portion of the life span during which function is sufficient to maintain autonomy, control, independence, productivity and well-being.

Eugene is an example of someone with a long lifespan and healthspan and this is what we truly seek, the combination of living well and living long.

Peter Attila writes that lifespan is driven by how long one can avoid the onset of diseases caused by atherosclerosis such heart attacks and strokes (see my  discussions on subclinical atherosclerosis here), cancer and neurodegenerative disease.

Healthspan,  Attila writes, is about preserving three elements of life as long as possible:

  1. Brain—namely, how long can you preserve cognition and executive function

  2. Body—specifically, how long can you maintain muscle mass, functional strength, flexibility, and freedom from pain

  3. “Spirit”—how robust is your social support network and your sense of purpose.

Problems with the body result in frailty, recognized as a major cause of disability and related falls, hospitalizations and death in the elderly.

The single best tool for warding off frailty appears to be physical exercise.

img_7051
Eugene and Noami tripping the light fantastic in our exam room

So, if you want to life a long life with lots of quality years at the
end of that life be like Eugene: swim and dance with your loved ones. Keep moving, stretch and exercise in some manner regularly.

Gerontologically Yours,

-ACP

Should Fitness Be A Vital Sign?

The skeptical cardiologist routinely probes his patients’ activity and exercise levels and encourages them to engage in 150 minutes of moderate exercise weekly. However, I’m somewhat skeptical of the benefit of treating such assessments as a vital sign (like blood pressure or heart rate)  as a recent AHA scientific statement suggests.

I can only envision still another item  on a chart checklist that will have to be recorded in the EHR or already over-worked physicians will have their payments withheld.

The AHA statement suggests that ideally we should be measuring  our patients’ fitness by obtaining  maximal oxygen consumption (VO2 max) utilizing an expensive and rarely utilized cardiopulmonary exercise test. Failing that we should consider doing a treadmill stress test. Failing that, rather than utilizing my simple question to patients: “How active have you been?”,  the statement recommends doctors utilize some sort of formal questionnaire to estimate their patients’ cardiorespiratory fitness (CRF) such as the one at World Fitness Level.

I went online to take this CRF estimator (based on this paper) and I remain skeptical.

The online site and  a free smartphone app both ask the following questions:

  • Country and City
  • Ethnicity
  • Highest Level of Education
  • Gender/Age/Height/Weight
  • Resting and Maximal Pulse
  • How often do you exercise?
  • How long is your workout each time? (over/under 30 minutes)
  • How hard do you train? (I had to choose between “I go all out”or “Little hard breathing and sweating”)

 

screen-shot-2016-12-03-at-11-33-13-amWhen you have finished answering the questions you are given an estimate of your fitness age. When I did this online a few days ago and answered truthfully I got the result to the right: I had the fitness of a 41 year old with an estimated VO2 max of 49 ! (interestingly this estimate corresponds exactly with VO2 max derived from a recent stress test I completed.)

I used the app (which unlike the online version did not ask me my waistline measurement) and changed a few parameters:

  • I increased my resting heart rate or pulse  from 60 to 68 beats per minute (BPM)
  • I increased my maximal heart rate from what I know is 158 BPM to what the app calculated (173 BPM, which makes no sense)
  • I switched from exercising 2-3 times per week  and longer than 30 minutes  at “all out” level to the lowest level for all 3 questions.

The change was dramatic and depressing: I went from 39 years old to 67 years old in the bat of an eyelid!img_8073

 

 

 

The app and online site direct you to a non-profit site where you can get information on a 7 week program to increase your fitness level. I haven’t checked this out.

I’ll be trying out this CRF estimator on my patients: assessing whether it adds anything to my usual line of questioning on activity and fitness.

I encourage you to give the CRF estimator a try. Let me know in the comments how you feel it works for you. Does it motivate you to exercise more knowing that, for example, your fitness age is substantially higher than your chronological age?