#71 - Aging, inactivity, atrophy and exercise with Professor Sue Bodine
Nov 5, 2023
auto_awesome
Dr. Glenn McConell chats with Professor Sue Bodine, an expert on muscle atrophy with inactivity/aging. They discuss muscle size reduction and loss of fast fibers with age, how resistance training can slow muscle atrophy, anabolic resistance, the role of hormones and protein synthesis in muscle aging, the amount of exercise needed to attenuate muscle atrophy, the importance of exercise after bed rest, and the impact of intense endurance exercise on muscle fiber size.
Resistance training can attenuate the rate of muscle atrophy associated with aging.
The loss of muscle strength with age is influenced by both the nervous system's ability to activate muscles and the decrease in muscle mass.
Resistance exercise and intense endurance exercise can prevent denervation of muscle fibers and the subsequent fiber type conversion.
Deep dives
Resistance training and muscle size
Resistance training increases muscle size (hypertrophy) while aging tends to lead to muscle atrophy. The reduction in muscle size with age is due to a combination of aging itself and inactivity. It is possible to slow the rate of muscle size loss by engaging in resistance training. Additionally, endurance training may also help slow the rate of muscle loss. Nutrition can also play a role in the rate of muscle atrophy with age, but there are other factors to consider beyond just muscle size and strength, such as balance.
Factors contributing to muscle strength loss with age
The loss of muscle strength with age is multifactorial. It is influenced by both the nervous system's ability to activate muscles and by the individual muscle fibers becoming weaker or smaller. Aging and inactivity contribute to the loss of muscle strength, as the nervous system may have difficulties activating muscles effectively and there may be a decrease in muscle mass. However, the ability to activate muscles efficiently may be improved through resistance exercise, leading to strength improvements before increases in muscle size. The rate of muscle strength loss typically accelerates beyond the age of 60.
Exercise, aging, and muscle response
Resistance exercise and intense endurance exercise can potentially slow down the loss of fast motor units and stabilize neuromuscular junctions, the connection between muscle fibers and nerves. This can prevent denervation of muscle fibers and the subsequent fiber type conversion. The response to exercise can be attenuated with aging, with older individuals experiencing an attenuated response to resistance exercise. Hormones such as testosterone and growth hormone may have less impact on muscle size maintenance in older individuals, with other factors possibly playing a more significant role. Proper nutrition, including adequate protein intake, is essential for muscle health, but excessive protein supplementation beyond recommended levels has not been shown to have additional benefits. Inactivity and chronic diseases can also contribute to muscle atrophy.
Importance of Exercise After Inactivity or Illness
After a period of inactivity due to illness or bed rest, it is crucial to engage in resistance training and rehabilitation to rebuild muscle strength and mass. Simply becoming mobile again is not enough, as many individuals do not fully recover to their previous baseline. Lack of intense rehabilitation can lead to accelerated muscle loss and decline in mobility, resulting in a spiral of inactivity. A focus on resistance training and endurance exercises is especially important after a period of inactivity.
Walking and Balance for Elderly Individuals
For older adults, maintaining an active lifestyle through activities like walking is key to slowing down the aging process. Walking can provide resistance exercise, particularly when done on hilly terrains. Additionally, balance exercises are crucial for fall prevention, as aging affects not only strength and aerobic capacity but also balance. Resistance bands or small weights can be used at home to incorporate resistance training into daily routines. Starting resistance training at any age can lead to beneficial muscle hypertrophy, although earlier initiation may yield better long-term results.
Dr Glenn McConell chats with Professor Sue Bodine from the Oklahoma Medical Research Foundation, Oklahoma, USA. She is an expert on muscle, in particular muscle atrophy with inactivity/aging. We chatted about how with age muscle size is reduced and this is associated with a reduction in muscle fiber size and also a loss of fast muscle fibers. Resistance training (and perhaps intense endurance exercise) can attenuate the rate of muscle atrophy. We discussed how much muscle atrophy is due to age per se and how much is due to inactivity. Anabolic resistance, protein synthesis, the importance of strength for balance etc. A very interesting chat. 0:00. Introduction + how Sue got into exercise research 5:25. What determines muscle strength 7:20. What age do we start losing muscle mass and strength? 8:40. Muscle atrophy and loss of fast muscle fibers 13:10. Can exercise training reduce the loss of fast fibers with age? 17:50. How muscle of muscle atrophy with age in inactivity? 19:20. Anabolic resistance with age 20:40. A role of hormones in muscle atrophy with age? 22:30. Protein synthesis and turnover in muscle with aging 26:46. How much exercise is needed to attenuate muscle atrophy? 30:30. Aging vs inactivity vs immobilizing vs bed rest etc 33:30. Importance of exercise after bed rest/immobilization 37:27. Upper body atrophy in runners/cyclist etc 39:55. Intense endurance exercise and slow muscle fiber size 43:00. Need to actually work out not just turn up 44:42. Exercise prescription with aging 47:05. Balance with age/inactivity 48:45. Diet and muscle atrophy 50:00. Need a stimulus (ex training) not eating more protein 54:52. Disease processes and muscle atrophy 58:10. Mechanisms playing a role in muscle atrophy/hypertrophy 1:08:53. Don’t need to break down muscle to build muscle 1:10:40. Determining muscle quality/specific tension 13:02. Are slow fibers really weaker than fast fibers? 1:17:22. Takeaway messages 1:18:53. Can very old people still get stronger/hypertrophy? 1:19:50. Do females really hypertrophy less? 1:22:00. Outro Inside Exercise brings to you the who's who of research in exercise metabolism, exercise physiology and exercise’s effects on health. With scientific rigor, these researchers discuss popular exercise topics while providing practical strategies for all. The interviewer, Emeritus Professor Glenn McConell, has an international research profile following 30 years of Exercise Metabolism research experience while at The University of Melbourne, Ball State University, Monash University, the University of Copenhagen and Victoria University. He has published over 120 peer reviewed journal articles and recently edited an Exercise Metabolism eBook written by world experts on 17 different topics (https://link.springer.com/book/10.1007/978-3-030-94305-9). Connect with Inside Exercise and Glenn McConell at: Twitter: @Inside_exercise and @GlennMcConell1 Instagram: insideexercise Facebook: Glenn McConell LinkedIn: Glenn McConell https://www.linkedin.com/in/glenn-mcconell-83475460 ResearchGate: Glenn McConell Email: glenn.mcconell@gmail.com Subscribe to Inside exercise: Spotify: shorturl.at/tyGHL Apple Podcasts: shorturl.at/oFQRU YouTube: https://www.youtube.com/@insideexercise Anchor: https://anchor.fm/insideexercise Google Podcasts: shorturl.at/bfhHI Anchor: https://anchor.fm/insideexercise Podcast Addict: https://podcastaddict.com/podcast/4025218 Not medical advice
Remember Everything You Learn from Podcasts
Save insights instantly, chat with episodes, and build lasting knowledge - all powered by AI.
