May 28, 2024 • 2hr 31min

#090 How Exercise Prevents & Reverses Heart Aging | Benjamin Levine, M.D.

FoundMyFitness

Dr. Benjamin Levine is one of the world's leading experts in understanding how the heart adapts to various conditions including exercise, elite athleticism, bed rest, and even microgravity. He is the founding director of the Institute for Exercise and Environmental Medicine at UT Southwestern in Dallas. In this episode, Dr. Levine discusses his groundbreaking research showing how exercise can reverse aspects of cardiac aging, even in previously sedentary individuals. He explains the physiological adaptations that occur with different types and doses of exercise, as well as potential risks of extreme endurance training. The conversation covers optimal exercise prescriptions for health vs. performance, recovery strategies, s*x differences in fitness, and much more.

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Key Takeaways

Three weeks of bed rest produces a functional decline worse than 30 years of aging - A landmark study found that 3 weeks of bed rest in young men caused greater declines in fitness than 30 years of aging
Exercise can reverse up to 20 years of heart aging in late middle age - A 2-year exercise intervention in sedentary 50-65 year olds was able to reverse many aspects of cardiac aging
4-5 days per week of exercise over a lifetime is optimal for preserving youthful heart structure - Studies show 4-5 days/week of exercise throughout life maintains cardiac compliance similar to younger adults
High-intensity interval training provides unique benefits - Incorporating high-intensity intervals like 4x4 min at 95% max effort is important for improving aerobic power
Recovery is critical for reaping exercise benefits - Adequate recovery between intense sessions allows physiological adaptations to occur
Resting heart rate is the best indicator of overtraining - Monitoring early morning resting heart rate can signal when more recovery is needed
Heart rate variability (HRV) is not a reliable recovery metric - HRV is too variable and technique-dependent to be used reliably for monitoring recovery
Extreme endurance exercise increases risk of atrial fibrillation - Very high volumes of endurance training (>10 hrs/week) raise Afib risk, though moderate exercise is protective
Exercise does not remove plaque but may stabilize it - Higher intensity exercise appears to reduce soft plaque formation while very long duration may increase calcification
Becoming an endurance athlete will not necessarily extend lifespan - There is no evidence that extreme endurance training prolongs life beyond more moderate exercise

Introduction

Dr. Benjamin Levine is one of the world's leading experts in understanding how the heart adapts to various conditions including exercise, elite athleticism, bed rest, and even microgravity. He is the founding director of the Institute for Exercise and Environmental Medicine at UT Southwestern in Dallas.

In this episode, Dr. Levine discusses his groundbreaking research showing how exercise can reverse aspects of cardiac aging, even in previously sedentary individuals. He explains the physiological adaptations that occur with different types and doses of exercise, as well as potential risks of extreme endurance training. The conversation covers optimal exercise prescriptions for health vs. performance, recovery strategies, s*x differences in fitness, and much more.

Topics Discussed

Effects of Bed Rest on Cardiovascular Health (6:41)

Dr. Levine discusses the landmark Dallas Bed Rest study, which found that 3 weeks of bed rest in young men caused greater declines in fitness than 30 years of aging. Key points:

Bed rest causes rapid declines in heart size, muscle mass, and maximal oxygen uptake
It took previously fit individuals longer to regain fitness after bed rest compared to unfit individuals
The negative effects of bed rest highlight the importance of movement and exercise for maintaining health

Exercise and Reversing Cardiac Aging (24:22)

Dr. Levine explains his research showing exercise can reverse aspects of cardiac aging:

A 2-year exercise intervention in sedentary 50-65 year olds reversed up to 20 years of cardiac aging
The program included high-intensity intervals, moderate aerobic exercise, and strength training
Improvements were seen in cardiac compliance (stretchiness of the heart)
Starting exercise earlier in life (before age 65) appears to be key for reversing aging effects

Optimal Exercise Dose for Cardiovascular Health (22:14)

Dr. Levine outlines the research on optimal exercise frequency for maintaining youthful heart structure:

4-5 days per week of exercise throughout life maintains cardiac compliance similar to younger adults
2-3 days per week was not enough to preserve youthful heart structure
Competitive athletes (6-7 days/week) had the most youthful hearts, but this level is not necessary for health

High-Intensity vs. Moderate Intensity Training (42:42)

The discussion covers the unique benefits of high-intensity training:

High-intensity intervals like 4x4 min at 95% max effort are very effective for improving aerobic power
Moderate intensity has benefits for vascular health and is lower risk
An ideal program incorporates both high-intensity and moderate sessions

Recovery and Overtraining (1:43:26)

Dr. Levine emphasizes the importance of recovery between intense training sessions:

Recovery allows physiological adaptations to occur after training stimuli
Early morning resting heart rate is the best indicator of overtraining
Heart rate variability (HRV) is not reliable enough to use for recovery monitoring

Cardiorespiratory Fitness and Longevity (51:01)

The conversation covers why higher cardiorespiratory fitness (VO2 max) correlates with lower mortality risk:

Higher fitness preserves cardiac structure and function
It improves vascular health, autonomic tone, and mitochondrial function
Fitness helps manage chronic diseases like hypertension and diabetes

Risks of Extreme Endurance Exercise (2:08:45)

Dr. Levine discusses potential risks associated with very high volumes of endurance training:

Increased coronary artery calcification, though the clinical significance is debated
Higher risk of atrial fibrillation, particularly in older endurance athletes
No clear evidence of increased mortality risk with extreme endurance training

S*x Differences in Exercise Physiology (2:00:02)

The discussion covers physiological differences between men and women in exercise performance:

Men tend to have higher VO2 max and performance due to effects of testosterone
Women may have some cardioprotective effects from estrogen pre-menopause
Post-menopause, women's cardiovascular risk becomes more similar to men

Exercise Recommendations for Health vs. Performance (47:39)

Dr. Levine outlines his exercise recommendations:

For health: 4-5 days/week mixing high-intensity, moderate aerobic, and strength training
For performance: Training volume/intensity depends on specific sport/event goals
Make exercise part of your "personal hygiene" routine, like brushing teeth

Conclusion

This wide-ranging discussion with Dr. Benjamin Levine provides valuable insights into how exercise affects cardiovascular health across the lifespan. Key takeaways include the ability of exercise to reverse aspects of cardiac aging, even in previously sedentary individuals, as well as optimal exercise prescriptions for maintaining heart health. Dr. Levine emphasizes the importance of incorporating both high-intensity and moderate training, while allowing for adequate recovery.

The conversation also covers potential risks of extreme endurance training, though moderate-to-high levels of exercise appear to be broadly beneficial for health and longevity. Overall, Dr. Levine's research demonstrates the profound ability of exercise to modulate cardiovascular aging and health, while providing practical recommendations for exercise programming to optimize both health span and performance.