Who isn’t interested in slowing down the aging process? One hormone that starts to decrease after adolescence is human growth hormone. By the time you reach your mid-40s, you only have about a third of the growth hormone you had when you were young. Why is this significant? Growth hormone helps preserve many of the characteristics that keep us looking and feeling youthful. Take a look at some of the benefits growth hormone has:
. Helps preserve healthy bones
. Aids in fat loss
. Enhances exercise performance
. Helps preserve muscle mass (by increasing IGF-1)
. Improves energy level
One of the reasons body composition changes with age is related to a drop in growth hormone. So powerful is the impact of growth hormone on aging that some people turn to growth hormone injections to slow the aging process. Keep in mind this anti-aging strategy is not approved by the FDA. No wonder! Human growth hormone injections, in addition to being expensive, cause side effects like joint pain, fluid retention, breast enlargement, and increase the risk for carpal tunnel syndrome, and, possibly, cancer.
High-Intensity Interval Training and Growth Hormone
Taking growth hormone injections isn’t a smart or safe way to ward off the effects of aging. However, there’s another way to increase your growth hormone level – and it’s all natural – high-intensity interval training or HIIT.
HIIT training is a super-intense but speedy way to work out. It also offers anti-aging benefits you don’t get from moderate-intensity cardio. The reason? High-intensity growth hormone boosts growth hormone release more than moderate-intensity aerobic exercise. In one study, human growth hormone levels markedly increased with only 10 minutes of high-intensity exercise.
According to a study published in Sports Medicine, an exercise that exceeds the lactate threshold, as HIIT training does, may increase the release of growth hormone by the pituitary gland even at rest. Another way to maximize growth hormone release is to make sure you’re getting enough quality sleep. It’s during deep sleep and vigorous exercise that growth hormone is released.
Other Reasons HIIT Training Combats Aging
Another change that happens as we age, especially after menopause, is a gradual decline in insulin sensitivity. When insulin sensitivity drops, it forces your pancreas to produce more insulin to get glucose into cells. As your pancreas struggles to meet the demand, you end up with higher levels of insulin circulating in your blood stream.
With so much insulin floating around, it’s easier for your fat cells to store fat, especially around the waistline and tummy. Ever notice how people over the age of 50 are more likely to have a “muffin top?” That’s partially due to a poor diet and lack of exercise, but it’s also fueled by a reduction in insulin sensitivity.
Improves Insulin Sensitivity
What does this have to do with HIIT training? Exercise, in general, boosts insulin sensitivity, but more intense exercise does it more. Some studies show high-intensity interval training increases insulin sensitivity by as much as 58%. Plus, some, but not all research, shows HIIT is better than moderate-intensity exercise for shedding belly fat. This is likely due to the powerful impact HIIT training has on fat-burning hormones like growth hormone, epinephrine, and norepinephrine. The stress of high-intensity interval training causes a significant rise in all of these fat-burners. In one study, growth hormone levels remained 10 times higher over baseline an hour after a HIIT treadmill workout. Like growth hormone, epinephrine, and norepinephrine, also known as catecholamines, boost the release of fat from fat stores.
Longer duration moderate-intensity exercise also increases catecholamine release but not to the same degree. With HIIT, you also get the benefit of the afterburn effect where you burn more body for hours AFTER a workout. This additional energy expenditure adds up over time. In addition, some studies show high-intensity interval training suppresses appetite. All in all, HIIT training combats the drop in insulin sensitivity and the increase in tummy fat many people experience once they reach middle-age.
Your Heart Ages Too
Heart disease is still the number one “old age disease” and the leading cause of death. A number of studies show high-intensity interval training is superior to steady-state exercise for cardiovascular health. For example, a study published in the Journal of the American Medical Association found a 4% reduction in heart disease risk for every one-MET increase in exercise intensity. Because of these benefits, more cardiologists are encouraging patients who have coronary artery disease to do supervised high-intensity exercise. Of course, you should always check with your doctor before exercising vigorously if you have a history of heart disease.
Preservation of Lean Body Mass
HIIT training, unlike moderate-intensity cardio, activates fast-twitch muscle fibers, making it more effective for preserving lean body mass. Combine HIT training with resistance training and it helps offset the loss of muscle mass that goes along with aging. What about bone health? High-intensity interval training is effective here too. Although any type of impact exercise helps preserve bone density, HIIT training gets the job done in a time-expedient manner.
Does HIIT Training Slow Aging at the Cellular Level?
Here’s an exciting finding. Research shows high-intensity exercise activates an enzyme called telomerase that helps prevent shortening of telomeres inside cells, a factor linked with aging. Telomeres are short sequences of DNA at the tips of chromosomes that protect chromosomes from damage – a good thing, especially since your DNA is exposed to damaging free radicals. Unfortunately, telomeres shorten with age, making it harder for cells to replicate. By activating telomerase, HIIT training potentially allows cells to survive longer. So, HIIT training may slow down aging at the cellular level.
The Bottom Line
With so many ways high-intensity interval training slows aging, you can feel good about making it part of your fitness routine. It’s not easy, but HIIT training is effective not only for the anti-aging benefits it offers but for increasing aerobic and anaerobic fitness. It’s also an excellent stress reliever. Now you know why it’s so important to do high-intensity interval training.
References
Sports Med. 2003;33(8):599-613.
Harvard Health Publications. “Growth hormone, athletic performance, and aging”
JAMA Vol. 288. No. 16. October 23/30, 2002.
European Society of Cardiology. “The impact of high-intensity interval training in CAD patients”
Circulation. 2012; 126: A18220. December 8, 2015.
Am J Epidemiol. 2012 Mar 1;175(5):414-22. doi: 10.1093/aje/kwr330. Epub 2012 Feb 1.
J Clin Endocrinol Metab. 1992 Jul;75(1):157-62.
J Clin Endocrinol Metab. 2000 Feb;85(2):799-803.
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High-Intensity Interval Training: How Long Should Your Active Intervals and Recovery Periods Be?
High-Intensity Interval Training: How Intense Does It Have to Be?
How High-Intensity Interval Training Slows Aging at the Cellular Level
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