General Adaptation Syndrome: the Athlete’s Response to Stress

In the 1930s, Hans Selye discovered and documented that stress differs from other physical responses in that stress is stressful whether one receives good or bad news, whether the impulse is positive or negative. He called negative stress “distress” and positive stress “eustress.” He also pointed to an “alarm state,” a “resistance state,” and an “exhaustion state.”

“Every stress leaves an indelible scar, and the organism pays for its survival after a stressful situation by becoming a little older.” ~ Hans Selye

Perhaps the most interesting aspect of my 3-week EMT course was the physical side of the stress I felt. The progression went something like this:

  • During the first week of school, determined to maintain a sustainable effort of exercise, I ran 6 miles every morning and 18 miles over the weekend.
  • On Monday of the second week, I was too tired to run. After re-grouping, I decided on a more realistic training schedule of 20 miles for the week.
  • On Monday of the third week, I quit running altogether.

My body tried to adapt to the new stressor of school but when the stress did not end, my body lost its battle to resist the stress and gave up. It was during the second week of class that we learned about Diabetic Emergencies and practiced checking each other’s glucose levels. We were looking for a normal reading of 80-100. My sugar was the highest in the class at 140. The next morning I checked it again – it was 150. I’ve continued to monitor my glucose levels now that I’m out of class. Yesterday I tested at 101 and today was 98, normal levels.

The physical effects of stress range from an increased heartbeat to shallow breathing. This is because there’s a greater flow of oxygen into the body. Your pupils will dilate to allow more light to enter your eye. All of these things happen because of a release of adrenaline — the body’s main stress hormone. There’s also a release of cortisol, another stress hormone, by the adrenal gland. Cortisol will jack up your blood pressure and blood sugar. Your liver will begin to manufacture some glucose to provide you with extra energy. After your stress goes away you may feel a physical crash — this is because of the extra glucose you’ve burned off. It essentially leaves you with a low supply of blood sugar, like when you haven’t had anything to eat all day. If the stress never goes away, hypertension (high blood pressure) begins to build and real damage occurs. The more your body’s stress system is activated, the harder it is to shut off.

Athletes can use this information to guide training efforts.

Selye eventually developed the idea of two “reservoirs” of stress resistance, or stress energy. Selye conceptualized the physiology of stress as having two components: a set of responses which he called the “general adaptation syndrome,” and the development of a pathological state from ongoing, unrelieved stress.

He first described the General Adaptation Syndrome (GAS) as the predictable way in which the body restores itself to balance, or homeostasis, in response to stress. The GAS is what offers important applications for designing effective sports training programs.

Russian sports training theorists used his ideas in the 1960s to explain how an athlete’s performance improved with the correct application of training stresses. GAS theory also offered a physiological rationale as to why adequate recovery was an essential part of the athlete’s training program, and exercise physiologists began exploring adaptations taking place due to different forms of training stresses.

The General Adaptation Syndrome has three phases:

ALARM STAGE: At this stage everything is working as it should – you have a stressful event (or training event), your body alarms you with a sudden jolt of hormonal changes, and you are now immediately equipped with enough energy to handle it.

Alarm Stage Danger: During this phase the main stress hormones, cortisol, adrenaline, and noradrenaline, is released to provide instant energy. If this energy is repeatedly not used by physical activity, it can become harmful.

Too much adrenaline results in a surge of blood pressure that can damage blood vessels of the heart and brain – a risk factor in heart attack and stroke. The excess production of the cortisol hormone can cause damage to cells and muscle tissues. Stress related disorders and disease from cortisol include cardiovascular conditions, stroke, gastric ulcers, and high blood sugar levels.

RESISTANCE STAGE: The adaptation stage occurs if the stress continues or recurs for a period of time. In this stage, the body makes adjustments in its structures or enzyme levels to give it added protection against this specific type of stress.

Rest must occur in order for recovery and rebuilding to take place.  Homeostasis begins restoring balance and a period of recovery for repair and renewal takes place. Stress hormone levels may return to normal but you may have reduced defenses and adaptive energy left.

Resistance Stage Danger: If a stressful condition persists, your body adapts by a continued effort in resistance and remains in a state of arousal. Problems begin to manifest when you find yourself repeating this process too often with little or no recovery. For athletes, this could be not enough recovery between speed sessions or rest days after a target race. Ultimately this moves you into the final stage.

EXHAUSTION STAGE: At this phase, the stress has continued for some time. Your body’s ability to resist is lost because its adaptation energy supply is gone. Often referred to as overload, burnout, adrenal fatigue, maladaptation or dysfunction. Stress levels go up and stay up.

Exhaustion Stage Danger: Injury and/or Illness

Chronic stress can damage nerve cells in tissues and organs. Particularly vulnerable is the hippocampus section of the brain. Thinking and memory are likely to become impaired, with tendency toward anxiety and depression. There can also be adverse function of the autonomic nervous system that contributes to high blood pressure, heart disease, rheumatoid arthritis, and other stress related illness.

Dr. Christine Brooks, B.Sc., ND, training theory and physiology specialist, recommends several key points to follow when incorporating the General Adaptation Syndrome in your training:

1. The purpose of training is to cause the body to adapt to sport-specific stressors. Training should (a) strengthen physiological systems, (b) mobilize the correct energy systems and fuel supplies, and (c) repair damaged cells.

2. Use a training stress that produces a recoverable level of fatigue within a reasonable amount of time. The optimal training program stimulates adaptations by causing a recoverable level of fatigue to the cells and organ systems. After each bout of training the athlete should feel fatigued to some degree, but not so exhausted homeostasis is disturbed to the point of overtraining.

3. Always incorporate the recovery time as a recognizable part of the training program. Once the structural and enzyme protein adaptations have occurred the body will be at a higher physiological level of functioning.

4. Recovery should be long enough to allow for supercompensation. During supercompensation the internal body structures, enzymes, energy and fuel stores build beyond the normal biological state. The effect is specific. While the goal is for the total recovery period for younger athletes, including supercompensation to be around 24 hours this could be as short as 8 hours or longer than 24 hours for the higher trained or aged athletes.

5. Remember the principle of reversibility. You don’t want the athlete to have such a long time to recover that detraining begins.


Test your knowledge:

1. Physiologically, the purpose of training is to:

a) cause the body to adapt to sport-specific stressors. b) develop fast-twitch muscle fibers. c) prevent anxiety. d) improve strength and endurance.


2. If an athlete does not allow the body to recover from long-term stress _______________ will occur.

a) injury b) overtraining c) lack of adaptation d) all of the above


3. Sprinting and weightlifting are examples of:

a) aerobic training. b) concurrent training. c) anaerobic training. d) stressing the cardiovascular system.


4. The effects of aerobic training include:

a) reduced stroke volume. b) an increased number of mitochondria. c) the ability to use proteins as fuel. d) None of these.


Answer key:

1.a, 2.d, 3.c, 4.b


Additional Resources for anyone dealing with stress:

The Physical Side of Stress