Metabolic Aging: How Key Hormones Are Affected by Aging

Metabolic Aging: How Key Hormones Are Affected by Aging

Aging is an ongoing process of change and not all the changes that take place are bad. Most of us would like to hang on to the wisdom we’ve gained from experience and the passage of time, but would rather not deal with the wrinkles, weight gain, and frailty that go along with it!

Along with aging come changes in key hormones that contribute to the aging process and are responsible for many of the changes we see like increased body fat, a reduction in lean body mass, frailty, and health problems like bone loss. Let’s look at these hormones, how they change with age, and what you can do to offset these changes to some degree, and, hopefully, slow down the aging process.

 Metabolic Aging: Insulin

Insulin has a bad reputation for causing weight gain, but we wouldn’t be alive without it. It’s insulin that helps ferry glucose and amino acids into cells where cells can use them to make energy. When there’s an abundance of energy, these macronutrients are stored as glycogen or fat for later use. Insulin only becomes a problem when cells become resistant to it and levels start to slowly rise. That’s exactly what happens as we age.

Although insulin resistance is strongly linked with being overweight or obese, insulin sensitivity tends to drop with age even in cases where body weight remains the same. Unfortunately, as insulin sensitivity declines, it makes it harder to lose weight, which partially explains why people gain weight with age. If you notice more fat around your midline, even if your weight is remaining stable, that’s likely a reflection of decreased insulin sensitivity.

What can you do about the gradual loss of insulin sensitivity? A study published in Sports Medicine showed aerobic exercise and resistance training are powerful weapons in the battle against insulin resistance. Physical activity can offset the effects of declining insulin sensitivity independent of weight loss. Of course, losing weight, if you’re overweight, will also improve glucose metabolism and make your cells more sensitive to insulin.

Why is it so important to take insulin resistance seriously? Insulin resistance is linked with many age-related health problems, including type 2-diabetes, heart disease, obesity, and even Alzheimer’s disease. There’s also evidence that insulin resistance itself contributes to biological aging.

The take-home message? Staying physically active and maintaining a healthy body weight are the two most important things you can do to enhance insulin sensitivity and reduce the impact of metabolic aging. Just as importantly, eliminate processed foods and sugar from your diet and eat more fiber-rich whole foods and lean sources of protein.

Metabolic Aging: Growth Hormone

Growth hormone levels decrease with age and one of the consequences of this decline is a decrease in lean body mass. Growth hormone stimulates muscle protein synthesis and exerts many of its effects on muscle tissue via another hormone called insulin-like growth factor or IGF-1, produced by the liver. Growth hormone and IGF-1 levels both go down with age, although you continue to produce it throughout life, mostly during deep sleep. The “master gland” in your brain called the pituitary produces growth hormone, but once made it only stays in your system a short time, long enough to tell your liver to produce IGF-1.

Unfortunately, compared to your 20s, by the age of 60, the amount of growth hormone your pituitary produces will be cut by half. This drop in growth hormone and IGF-1 partially explains why people lose lean body mass and gain fat with age and why some people become frail.

Is there a natural way to boost growth hormone production as you age? An amino acid called arginine is known to stimulate growth hormone release from the pituitary gland so getting adequate dietary protein works in your favor. Research also shows another amino acid, glutamine, turns on growth hormone synthesis. On the other hand, insulin reduces the release of growth hormone, so limiting processed carbs, sugar and eating more fiber-rich foods, may be of benefit.

Another way to maximize growth hormone release is to do anaerobic exercise at an intensity that exceeds your body’s lactate threshold, the point at which lactic acid builds up. A study showed growth hormone levels are higher for a full 24 hours after an anaerobic exercise session. So, spend a portion of your workout time doing high-intensity interval training and heavy resistance training as opposed to focusing on steady-state cardio and lifting light weights.

Since growth hormone is released in a pulsatile fashion during deep sleep, make sure you’re getting enough sleep and the sleep you’re getting is high quality. Block all of the light out of your room to maximize growth hormone release and ensure you enter deep, undisturbed sleep.

Metabolic Aging: Sex Hormones

After menopause, women lose estrogen produced by the ovaries as well as progesterone, although fat cells continue to make testosterone, particularly in women who are overweight. Testosterone produced by fat cells is converted to estrogen by an enzyme called aromatase, so women who have more body fat have higher levels of estrogen after menopause than lean women. Men experience a gradual decline in testosterone with age, but in women the change is more abrupt.

What happens when you lose estrogen and progesterone? You may experience a decrease in bone density, especially if you’re not doing high-impact exercise and high-intensity resistance training, and see more wrinkles and saggy skin appear as collagen synthesis in the dermis of the skin declines. You also may experience more joint aches and stiffness. By its effects on collagen, estrogen keeps your joints and ligaments supple and flexible.

Although you could take hormone replacement therapy, for most women, the risks aren’t worth it.  What can you do from a natural standpoint?

Make sure you’re high-intensity weight training to strengthen the muscles that support your joints and to stimulate new bone formation. Combine HIIT training with stretching to improve flexibility.

Make sure you’re eating plenty of vitamin C-rich fruits and vegetables to support healthy collagen production.

Eating foods that contain phytoestrogens, weak forms of estrogen from plant sources, help you get some of the benefits of estrogen without the risks of taking hormone replacement therapy. Good sources include unprocessed, organic tofu and tempeh, flaxseed, beans, lentils, miso paste, hummus, and pistachios.

Eat fatty fish twice a week to feed your body long-chain omega-3 fats for joint health.

Make sure you’re getting adequate amounts of calcium and vitamin D for bone health.

To ward off those age-related wrinkles and skin sagging, wear a protective, mineral-based sunscreen and consider using a product with glycolic acid or retinoic acid to boost collagen production.

The Bottom Line

These are a few of the hormones that have a significant impact on aging. You can’t completely stop the aging process but lifestyle counts when it comes to successful aging.



Diabetes. 2012 Jun; 61(6): 1315-1322.

Sports Med. 2003;33(8):599-613.

Sports Med. 2000 Nov;30(5):327-46.

Am J Clin Nutr. 1995 May;61(5):1058-61.

Harvard Health Publications. “Growth Hormone, Athletic Performance, and Aging”

Life Extension Magazine. “The Growing Impact of Growth Hormone”

Metabolism. 1999 Sep;48(9):1152-6.


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5 Hormones and How They Affect Your Body Composition

Growth Hormone and Exercise: What Role Does It Play?


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