Recovery
Recovery from hard workouts or racing essentially includes two parts:
- Restoring the energy stores such as glycogen store that are greatly consumed and very often depleted.
- Healing tissue (mostly muscle) damage.
- Restore the impaired immune system
The first part is relatively easy, but may be tricky sometimes . A typical example is recovering from a marathon that depletes the glycogen store. Intuitively, one would take a lot of carbohydrate (e.g. sweet food) to replenish the carbohydrate store. This assumes that the body functions normally in terms of digestion. This assumption may not be true. A strenuous exercise such as a marathon not only depletes the glycogen store, also causes many imbalances in the body (such as electrolyte imbalance). The body is not functioning normally in many senses after a prolong exercise. Trying to force the body to take something may be counter-productive in recovery. Fortunately our body uses its appetite to tell us what it needs as a part of its homeostasis. Listening to the body closely and following the appetite during the first 3-6 hours after a strenuous exercise may be the best approach for restoring energy stores and the normal function of the body. It is shown that a drink with carefully calculated amounts of electrolytes enhances recovery (Wong, et al, 1998); but this is impractical to do regularly for most athletes.
The second part is much more complicated. Complete rest is rarely the best way to heal tissue damages. The healing can be accelerated by enhanced blood perfusion coming from light exercise, massage or medicine. Complete healing of damages may take many days. Obviously one does not have to wait for the complete recovery to start another hard workout. There are studies showing strenuous exercise does not exacerbate muscle damage (Chen TC and Hsieh SS, 2000, Nosaka K and Clarkson PM, 1995). Light exercise is shown to reduce the decrease of circulating white blood cells caused by strenuous exercises (Wigernaes, 2000). The questions are: How light the light exercise for recovery should be? How soon after the hard workout should it take place? The answers to these question depend on many factors such as body conditions, age and the intensity of the strenuous workout. There are many programs for recovering from marathon. In training, the rule of thumb is alternating hard and easy training days. The intensities of both hard and easy workouts can be increased with the improvement of body conditions. The exact recovery process has to be experimentally figured out by practicing. In training, the recovery should allow the next hard workout to be performed at the same or better level than the previous one. If not, it means the light exercise is not light enough, the interval between hard workouts is not long enough or the hard workouts are too hard. The cool-down light exercise immediately after a hard workout reduces accumulated lactic acid quickly (McLoughlin P, et al. 1991).
Runners need more carbohydrate and protein than sedentary people. The damage of muscle tissue and the catabolism of protein in endurance training call for more protein. This can be achieved easily by increase the consumption of our staples and meat. We also need more other substances than sedentary people. We may get some of them by just eating more different kinds of natural foods. We may need some artificially fortified or enriched food, or even supplements to get others.
It is commonly accepted that runners need extra iron or calcium. The dynamics (constant remodeling) of runners' bones is more intensive than sedentary people and consumes more calcium. There is also more intensive hemolysis in runners resulting in extra iron loss. Tofu is an very good alternative of meat for runners because it is rich in calcium, protein and iron.
A strong immune system (our body's complex defense system) is essential for recovery and health. If the immune system is weakened, the danger of having diseases increases. If the weakening is permanent (e.g. AIDS), the life is in danger. The relationship between the immune system and exercises is only partially understood (Nieman and Pedersen, 1999). However it is commonly accepted that a prolonged strenuous exercise is followed by a temporary functional immune impairment (Steensberg, et al., 2001). That impairment lasts 3 to 72 hours. The author's personal experience shows the immune system can be impaired for a long time (e.g. months) if a new unaccustomed high level of training is reached rapidly. Generally speaking, the immune system can adapt to different levels of training and maintain normal functions just like other systems. Balanced diet is very important to keep a healthy immune system ( Shephard and Shek, 1998).
The way we can help the immune system is to supply it with adequate nutrients. This is where the buzzword "antioxidant" comes. Not only antioxidants but also Iron, zinc, calcium, and magnesium ion influence immune functions ( Shephard and Shek, 1998). It appears that most athletes have adequate status of zinc and magnesium (Clarkson, 1995). As for antioxidants (vitamin A, C, E, selenium) intake, the picture is very vague.
It is intuitive to increase the intake of antioxidants for endurance athletes because endurance training increases the production of radicals that can damage healthy cells and may even cause cancer. Antioxidants combat radicals by reducing them. Increasing antioxidants intake does not always increase the the concentration of antioxidants concentration in the body. Overdose of antioxidants also has negative effects. Cooper's Antioxidant Revolution (1994) is worth reading. The Web site Antioxidants and Exercise is a very good review. The general recommendation for athletes is that foods rich in anti-oxidants and minerals should be ingested rather than supplements (Clarkson, 1995).
A major increase in body fat can have adverse effects on immune response. In contrast, a negative energy balance and reduction of body mass are likely to impair immune function in an already thin athlete. A moderate increase in polyunsaturated fat enhances immune function, but excessive consumption can be detrimental ( Shephard and Shek, 1998)
References:
Chen TC and Hsieh SS (2000) The effects of repeated maximal voluntary isokinetic eccentric exercise on recovery from muscle damage. Res Q Exerc Sport 71(3):260-6.Clarkson PM (1995) Micronutrients and exercise: anti-oxidants and minerals. J Sports Sci. No:S11-24
McLoughlin P, et al. (1991) Gentle exercise with a previously inactive muscle group hastens the decline of blood lactate concentration after strenuous exercise. Eur J Appl Physiol Occup Physiol. 62(4):274-8
Nieman DC and Pedersen BK (1999). Exercise and immune function. Recent developments. Sports Med. 27(2):73-80
Nosaka K and Clarkson PM (1995). Muscle damage following repeated bouts of high force eccentric exercise. Med Sci Sports Exerc. 27(9):1263-9.
Shephard RJ and Shek PN (1998) Immunological hazards from nutritional imbalance in athletes. Exerc Immunol Rev 4:22-48
Steensberg, et al. (2001) Strenuous exercise decreases the percentage of type 1 T cells in the circulation. J Appl Physiol. 91(4):1708-12.
Wigernaes I, et al. (2000). Active recovery reduces the decrease in circulating white blood cells after exercise. Int J Sports Med 21(8):608-12
Wong SH, et al. (1998) Influence of fluid intake pattern on short-term recovery
from prolonged, submaximal running and subsequent exercise capacity. J Sports
Sci 16(2):143-52
(Originally written on 1/19/2002)
