SCIENCE FRIDAY: anti-aging exercise

Butterfly-friendly milkweed in bloom. Taken by PKSenagore July 5, 2017. All rights reserved.

DEEP DIVE INTO ANTI-AGING RESEARCH  In an article for Under Armor’s MyFitnessPal.com blog, “Can You Guess the Best Workout for Anti-Aging?”, author Jodi Helmer begins by reminding readers that inevitably our bodies change with age; “cell function decreases, bones lose density, joints show signs of wear and muscle tissue and strength decrease while body fat increases”. She goes on to provide advice from trainers and to summarize a few of the results of a Mayo Clinic research study, about the effects of different exercise training modes in old and young.
 
Helmer’s piece is very readable and helpful. If you want to delve much deeper into the science, Earned Runs has provided more information and some interpretation, below, on the details of this study recently published in the journal Cell Metabolism. The publication is “Enhanced Protein Translation Underlies Improved Metabolic and Physical Adaptations to Different Exercise Training Modes in Young and Old” by Matthew M Robinson M.D. and colleagues.
 
In two age groups of men and women, young (18-30 years) and older (65-80 years) this study compared the effects of 12 weeks of training by 3 different exercise modes supervised by an exercise physiologist:

1) Aerobic high intensity interval training (HIIT)
(HIIT cycling 3 days/week, > 90% VO2peak + steady walking 2 days/week, 70% VO2peak)

2) Strength resistance training (RT) at high intensity
(upper body and lower body, 60 minutes each day, total 4 days/week),

3) Combination training (CT) of aerobic and weight training, both at moderate intensity
(12 weeks of NO activity, then 12 weeks with steady cycling 5 days/week, 70% VO2 peak + upper and lower body weight training, 30 minutes each day, 4 days/week)
 
The research involved participants who were NOT regular exercisers prior to entering the study.  They were non-smokers and had no metabolic, heart, kidney, or vascular diseases, and were not obese.  The number of participants who completed all the requirements of the study was small in each exercise group, from 7-11.
 
Testing was performed at baseline (before) and after the 12-week exercise periods in the HIIT and RT groups; in the CT group, some baseline testing was performed before and after the initial 12-week period of inactivity, and then after the 12-week exercise period.
 
Some test results:

• Weekly energy expenditure (calorie burn): HIIT was greatest, then CT for both age groups; RT was lowest, less than half the calorie expenditure of HIIT
• Aerobic capacity (VO2peak): HIIT increased most for young, then CT; CT increased most for old, then HIIT.
• Fat free mass (muscle mass): increased in all exercise groups and both ages; RT showed greatest increase, then CT, then HIIT.
• Muscle strength: RT showed greatest increase, then CT; then HIIT but not significantly.
• Insulin sensitivity (rate of disappearance of glucose from blood: an important factor in diabetes prevention) RT was greatest then HIIT in both age groups; CT only had an effect in young group. [Fasting insulin and glucose levels did not change significantly in either group.]

Mitochondrial respiration (process by which nutrient energy is used to fuel cell activities)

• HIIT increased in both young and old, then CT only in young.

 
Gene expression change (from muscle biopsy):

• HIIT induced the largest change in skeletal muscle, regardless of age.
  • Gene expression change was greater in the HIIT older group (396 versus 274 genes); especially genes involved in mitochondrial, muscle-growth, and insulin signaling pathways
  • Data analysis suggested that “a large proportion of HIIT genes in the older age group is age specific.”

 

• Other types of analyses showed that exercise training did NOT reverse all age-related declines in genes but some specific patterns were detected in both young and old

 

• A “universal gene set” of 55 genes total was found to be upregulated across all training types and in both age groups that involves the formation and regulation of blood vessels, thus cardiovascular remodeling.

 
That’s a load of information! What is noteworthy about this study, and what do the results mean in terms of the ability of exercise type to counteract the effects of aging?
 
- The number of studied subjects was small. The details of race and ethnicity were not given, but with so few people there’s no guarantee the findings apply to everyone.
 
- Women and men were included. Studies often involve only men or only women.  In the older group, all the women were post-menopause. This is the time of life when bone density and muscle mass decline significantly.
 
- Study results show some things we already suspected:
--- Strength training performed at higher intensity is best for increasing fat free muscle mass and strength, and for increasing the sensitivity of the body to insulin, which helps prevent diabetes.
 
--- HIIT is best for calorie burning and increasing aerobic capacity, and assists with insulin sensitivity. HIIT doesn’t work as well to make muscle bigger or stronger, but it does work.
 
- Study results revealed some NEW information:
--- Exercise training did not seem to reverse all age-related declines in muscle gene expression
--- A “universal set” of muscle genes was upregulated (or boosted) by the 3 exercise modes in both age groups and this boost likely contributes to heart and blood vessel health.
--- HIIT induced the largest number of muscle gene expression changes in both age groups, but the effect was greatest in the older group and may be specific to older folks. 
 
- Potential good news for runners and walkers: the HIIT group had 5 days of workouts that included 2 sessions walking steadily (not intervals) on a treadmill for 45 minutes at 70% effort (VO2peak). It seems that 3 days of HIIT in which the greatest interval effort was cycling 4 minutes at >90%VO2peak followed by 3 minutes of low effort is enough to generate HIIT benefits.  Beyond those 3 days, walking at a higher intensity can be enjoyed by who wish to save their legs for running HIIT (speed intervals) or steady brisk walking.
 
- The study authors concluded that “supervised” HIIT seems to be an effective exercise mode to improve aspects of aging that relate to the health of our blood vessels and heart, and to metabolism (diabetes prevention).
 
--- Because the CT exercise mode (combination of moderate intensity aerobic and strength training) did not seem to produce results as good as aerobic HIIT alone, the researchers are indicating that high intensity is more beneficial than lower intensity aerobic exercise.  The comment emphasizes that exercise must be performed at this higher intensity level to generate the greatest anti-aging benefit, and that the direction of a trainer may be necessary to sustain interval exercise at this very high level.
 
Whew. This might have been too much science for some, but examining research closely allows us to learn more than what’s in brief media releases.
SUMMARY:

• HIIT provides greatest ANTI-AGING benefit
• OLDSTERS may experience more anti-aging benefits from HIIT than the younger set.
• To maintain muscle mass/strength in later years, STRENGTH TRAINING IS BEST.
• ALL modes of exercise benefit the cardiovascular system

 
RUN HAPPY!
 
http://blog.myfitnesspal.com/can-guess-best-workout-anti-aging
 
http://www.cell.com/cell-metabolism/fulltext/S1550-4131(17)30099-2
 
https://www.ncbi.nlm.nih.gov/pubmed/19949277