It has long been known that exercise is a key component in a prescription for a healthy lifestyle. With respect to the athlete, the issue is not whether you are getting enough exercise, but rather how exercise can be potentially harmful when it relates to your immune health. As an athlete, understanding the relationship between exercise and infection is very important for long term success.

The “J” Curve

Many individuals who begin an exercise routine often note that their immune health is much stronger since becoming athletic. As the athlete progresses in their training, however, there often comes a time when too much of a good thing becomes detrimental to the immune system. In the research, this is often noted as the “J” curve (see Figure 1) of exercise as it relates to infection, particularly upper respiratory tract infections (URTI). The model demonstrates that when an athlete engages in moderate exercise, the risk of infection decreases compared to someone who is sedentary. However, with high-intensity exercise (e.g marathon training), the risk of infection may rise above average and athletes may become more prone to infection.

Overtraining

The “J” curve concept can also be explained by defining some phases of athletic training. Overreaching is a period of training where the athlete is pushed to their limits, forcing the body to adapt to new levels of stress. The athlete will become physically and mentally fatigued, and performance may worsen for a time, but after adequate rest, their performance is even better. Overtraining occurs when an athlete is pushed to their limits without adequate rest, and performance degrades for two months or more. Overtraining syndrome is usually characterized by a decline in performance, chronic fatigue, depressed mood, sleep issues, reduced appetite, increased incidence of illness such as colds and flu, and increased incidence of injury such as strains, sprains and stress fractures, and much more. If not corrected, overtraining can lead to burnout or withdrawal from training for physical and mental health reasons.

Figure 1.

Stress and the Immune System

Overtraining syndrome has recently been recognized as a stress syndrome, paralleling the alarm, adaptation and exhaustion stages of stress or adrenal insufficiency. In fact, overtraining often results from a combination of intense training, inadequate rest and other life stressors. High levels of cortisol, the primary stress hormone, have been found in athletes experiencing overtraining. When cortisol is high, the body enters a catabolic state where survival is the priority, not repair. Vigorous exercise training damages the muscle and results in oxidative stress and inflammation. This is a normal part of the process of adaptation. The body enters a hyper anti-inflammatory stage which is followed by immunosuppression partly due to cortisol (considered an anti-inflammatory hormone). Here, the immune system is weakened for three to 72 hours, but this window of immunosuppression can be prolonged with repeated cycles of stress followed by inadequate rest and recovery time. This leaves room for increased risk of infection and injury. When overtraining is severe enough and burnout is imminent, cortisol levels will drop due to adrenal insufficiency and chronic fatigue, lethargy and apathy will set in, and illness and injury will be more prevalent.

Infection in Distance Runners

Research led by Nieman and colleagues measured the incidence of URTI for marathon athletes training for a race. It was determined that runners training more than 96 km/wk doubled their odds for illness compared with those training less than 32 km/wk. In another study by led by Peters and Bateman, they looked at the incidence of URTI in 150 randomly selected runners who took part in a 56 km race in South Africa and compared them to matched controls who did not run the race. Symptoms of URTI occurred in 33.3% of runners compared to 15.3% in controls during the two weeks after the race and were most common in those with the faster race times. Thus, it appears both distance and speed are factors in relation to immune system susceptibility.

Injury in Athletes

A study on college athletes determined an association between overtraining and injury. In this study, the average training regimen was two to three hours of moderate to intense training 4.5 days per week, and another two to eight hours/week of light or leisure exercise. The athletes felt physically exhausted 25-33% of the time during competition season, and 17-20% of the time in the off-season. Half of the athletes reported chronic injuries. Clearly, proper periodization, tapering and balancing training against other life stressors are vital to both the health and the performance of the athlete.

Supplements for Overtraining

Now let’s examine some potential supplement considerations to reduce the risk of infection due to overtraining and burnout.

B complex: This is a group of eight essential vitamins including vitamins B1 (thiamin), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B12 (cobalamin), folate and biotin. Adequate intake of B vitamins is important for optimum energy production and repair of muscle tissue. B-vitamins are quickly used up by the body during periods of stress, especially vitamin B5 in the form of pantethine. Vitamin B6 directly supports immune cell production. Vitamins B1, B2, B3, B5, B6 and biotin are involved in energy production during exercise while folate and vitamin B12 are required for the production of red blood cells (carry oxygen), protein synthesis (builds muscle), and in tissue repair. Vitamins B2, B6, B12 and folate are often found low in female athletes’ diets, especially those who are vegetarian or who suffer disordered eating patterns.

Magnesium: This mineral plays a variety of roles in cellular metabolism (of carbs, fats and proteins), regulates membrane stability and regulates neuromuscular, cardiovascular, immune and hormonal functions.

Magnesium deficiency impairs endurance performance by increasing oxygen requirements to complete submaximal exercise. Athletes in weight class (wrestling) and body conscious (gymnastics) sports have been reported to have inadequate dietary levels of magnesium.

Rhodiola is an herb known as an “adaptogen”. Adaptogens have the ability to help manage the effects of stress. Rhodiola has been shown to be very effective at modulating one of our stress hormones called cortisol. Under chronic stress or intense periods of exercise, cortisol remains elevated which causes impaired recovery for the athlete as well as lowered levels of sex hormones and a disrupted sleep cycle. For example, it is often noted that female athletes training at a high level will stop menstruating; this is a noted effect of elevated cortisol (although it can also occur due to low body fat). Additionally, a 2012 study showed that those athletes consuming Rhodiola before exercise displayed decreased heart rate, improved endurance and enhanced mood. Ginseng: Another herb in the adaptogen class, ginseng has been used for centuries in traditional Asian cultures. Panax ginseng (aka Red, Korean or Asian ginseng) has many medicinal properties derived from its active constituents known as ginsenosides. It has shown to be of benefit for many stressors including heat, cold, trauma, sleep deprivation, infection and intense exercise. In one study performed by Ziemba and colleagues, fifteen soccer players averaging 19 years of age were placed into two groups, placebo and ginseng. They were then placed on a bicycle ergometer at various stages until exhaustion was reached. Along the way, they were measured on reaction time, mental alertness and mental acuity. The study concluded ginseng does improve psychomotor performance and reaction time during exercise without affecting exercise capacity. Phosphatidylserine (PS): A naturally occurring compound of an amino acid (serine) bound to a phospholipid, PS is required for the functioning of all cells and is found in highest concentrations in the membranes of cells with high metabolic activity such as the brain, heart, liver and skeletal muscle. While previous research focused on the role of PS on the brain in relation to cognitive support and cognitive decline prevention, recent research has examined its role in athletics. A 1990 study examined the effects of PS on cortisol levels during exercise and demonstrated a blunting of cortisol when vigorous exercise was performed. This is a real positive because as previously noted, chronically elevated cortisol levels disrupt many systems in the body. The next phase of the study looked at the long term effects of PS supplementation on post exercise cortisol following strenuous resistance training. The results showed not only a continued blunting of cortisol, but also a lower level of perceived muscle soreness post-exercise, a real “win-win”.

Colostrum, also known as the “first milk”, makes up the first few meals of newborn mammals. It is produced in the breasts of the mother for several days after birth, followed eventually by regular milk. It provides the newborn with the necessary immune factors to fight infection, such as immunoglobulins, leukocytes, cytokines, lactoferrin and polyproline-rich peptides (PRP) so that the newborn can survive its first few days of life as well as prepare the immune system for lifelong protection. With direct application to athletics, one study looked at the effects of colostrum on immune variables in highly trained cyclists and concluded that colostrum balances immune parameters during normal training as well as after an acute period of intense exercise. This may have contributed to the trend toward reduced upper respiratory tract illness in this group.

Pelargonium sedoides: A memberof the geranium family of plants, this South African herbal has been used traditionally to treat issues of respiratory illness of both viral and bacterial origin. Its roots contain active chemical compounds known as phenols and coumarins which have shown immune boosting and antimicrobial effects. One of Pelargonium’s key features is its ability to help prevent the adherence of bacteria to the respiratory mucosa, thus minimizing colonization and infection. As upper respiratory infection is a common occurrence and complaint among athletes, this herbal may be worth considering especially after a bout of intense training.

Balancing it All Out As with many things, too much of a good thing can be bad. The same applies to exercise and athletics as it pertains to the immune system. It is important for the athlete to listen to their body cues when it comes to timing for rest and repair. Emphasis needs to be on the management of external stressors outside of training, appropriate sleep and diet. In addition, some key supplements may allow the athlete to rise even higher in their athletic pursuits as a result of their immune system being nourished.

What You Need to Know

Maintaining a high level of athletic performance and staying healthy in general all have related common factors. It is important to have a healthy diet and avoid excessive stress. However, supplements can help to fortify the body and prevent some of the pitfalls of overtraining including illness, injury and burnout. Certain vitamins, minerals, adaptogens and herbs are key supplements for supporting the body as an active person. Magnesium and B-vitamins are essential maintenance therapy for athletes. Herbal adaptogens such as Rhodiola and Asian ginseng can help prevent burnout and bolster the body against stress. Phosphatidylserine can help reduce cortisol levels. Colostrum directly supports the immune system and, along with Pelargonium sedoides, decreases the risk of upper respiratory tract infections among athletes.