New Insights Into How Testosterone, Growth Hormone & Cortisol Affect Health & Performance

Ever wonder why some days you feel upbeat and energized, ready to attack any challenge, whereas others you feel depressed and tired?

It all comes down to hormones:
Molecules produced in the body that communicate with cells throughout the body to dictate how you feel.

Hormones affect all aspects of human function, initiating protein synthesis and muscle contraction, regulating mood and wakefulness, and overseeing metabolism and fertility. They govern inflammation and affect your body’s ability to fight off chronic diseases, including diabetes and heart disease.

In recent years some of the biggest questions surrounding hormones have been the role of testosterone, growth hormone, and cortisol on health and body composition. A new review from sports scientists at Ohio State provides novel insight into the importance of these hormones.

Testosterone Is the Primary Anabolic Hormone In Men & It’s Also Important For Women
No surprise that testosterone is the primary anabolic hormone in men, having significant muscle building and performance effects. It is also important for women, though levels are radically lower and release following exercise is negligible. That said, research indicates that baseline testosterone is predictive of performance in women. Women who have higher levels are more likely to win any given competition.

Intense, high volume exercise leads to a significant increase in testosterone in men and previously it was theorized that this exercise-induced increase was a primary cause of hypertrophy, but more recent evidence indicates that the transient post-workout elevation is likely too small and short-lived to lead to noticeable changes in lean mass. Instead, scientists theorize that testosterone may upregulate cell receptors, which allows for greater testosterone binding as well as an enhanced neuromuscular drive, supporting strength.

Growth Hormone & IGF-1 Are Powerful Metabolic Hormones
Growth hormone and its cousin, insulin-like growth factor-1 (IGF-1) have related effects, though GH is best known for its fat burning properties, while IGF-1 is often thought of as a protein-stimulus hormone.

In fact, both GH and IGF-1 facilitate protein synthesis, aiding recovery from intense exercise or injury. They also stimulate fat burning and affect insulin signaling and the body’s use of carbohydrates.

Both are considered key recovery hormones. GH is involved in tissue repair and the greatest release occurs during sleep when it is secreted in bursts. IGF-1 is released from the liver in response to GH stimulation and it plays a key role in the body’s ability to manage inflammation following intense training or injury. IGF-1 is also produced locally in muscle tissues, which increases protein synthesis and is likely the mechanism via which IGF-1 increases hypertrophy.

Growth hormone and IGF-1 have been shown to respond to high-volume training, particularly the intense sort that raises blood lactate. For example, 6 sets of 10 reps of the squat at 80 percent of the 1 RM with 2 minutes rest between sets has been shown to produce large increases in GH and IGF-1. Younger and older individuals appear to have similar increases in these hormones in response to training and they are thought to have an anti-aging effect.

Cortisol Is A Metabolic Hormone With Catabolic Effects
Often thought of as a stress hormone, cortisol is a metabolic hormone whose main purpose is to raise blood glucose when the body is challenged. When balanced, it can be considered a protective hormone that is energizing and supports fat burning.

It’s only when cortisol gets out of balance that bad things happen: Too much of this hormone leads to increased belly fat storage, hunger, muscle loss, inflammation, and impaired sleep. Too little cortisol causes low energy and fatigue.

Cortisol is a perfect example of the cyclical nature of hormones: Cortisol peaks in the early morning to get you out of bed. Then it slowly curves downward over the course of the day with pronounced dips following meals. By nighttime, cortisol should be low so you can sleep.

However, this curve can be affected by extremes: Intense exercise, overwhelming chronic stress, lack of calories, and sleep deprivation all affect the body’s cortisol response. For example, the body pumps out cortisol in response to intense exercise, raising the overall cortisol curve for at least the 24 hours following a training session. In the immediate post-exercise period (6 to 24 hours) there is an increased tissue sensitivity to cortisol to counteract the muscle inflammatory response that damages muscle. This is followed by a decreased sensitivity following 24 hours to protect the body from the prolonged effects of exercise-induced cortisol secretion that would otherwise have a catabolic, muscle-wasting effect.

Hormone Release Follows A Domino-Like Cascade
If you learn one fact about hormones, it should be that most hormones influence secretion of other hormones in a cascading fashion. Everything is interrelated. The strength of each hormone’s message depends on various elements of the cascade.

A simple analogy is that hormone signaling is like playing a team sport. All players on the team have distinct roles and responsibilities during each play. Success depends on how well the team executes and communicates in an integrative manner to carry out team objectives. Hormones work in a similar manner.

A useful example is the normal circadian hormone cascade:

1) In the morning when you wake up, your body temperature is low and you get a surge in cortisol that increases blood pressure and gives you energy.

2) Exposure to light shuts off melatonin production (a hormone that induces sleep), and increases testosterone release, resetting the clock for the day

3) The body warms up through the middle of the day, and reaction time and physical performance peak between 2:30 and 6 pm.

4) As sunset approaches, light exposure is reduced, and cortisol drops.

5) You eat dinner and a few hours later, blood sugar and insulin will fall. As insulin is reduced, the hormone leptin is released to inhibit hunger.

6) Leptin causes thyroid hormone release to keep you warm and burn stored fat during the night, and it’s followed by melatonin release, which induces sleep.

7) Overnight growth hormone is released in a pulse-like fashion, which stimulates release of insulin-like growth factor, both of which have repair effects, initiating protein synthesis and overcoming inflammation.

There are both simple and complex ways the hormonal cascade can be disrupted, but the most common culprits include the following:

• Caffeine, alcohol, sugar, and other stimulants.
• Light exposure at the wrong times.
• Eating late at night.
• Excessive stress in the form of intense exercise, life stress, or calorie restriction.

Final Words:
This up-to-date knowledge about hormones will allow you to understand how the body works so that you can make a plan for optimal health and physical performance.