Nutrients and sport

Muscular exercise is a succession of movements, sometimes repetitive, that provide mechanical work.

These actions are the result of muscle contractions carried out as part of an engine program directed and controlled by the brain.
This program is different depending on the sport and on the purpose of each.
These muscle contractions involve more or less energy but not in astronomical proportions.

ENERGY NEEDS

They increase more or less depending on:
· The duration of the exercise
· The magnitude of the force
· The level of the practitioner, beginner or accomplished sportsman
· The type of sport
· Weight of the sports
· Its equipment, the weight of shoes, for example
· The nature of the terrain: walking on a sidewalk expends less energy than if walking takes place in a muddy field
· Of carrying a load or not.
The margin is very wide for all sports.
A game of tennis is spend 150 to 400 calories or more per hour.

PROTEIN
Proteins are the essential constituents of the muscles.
Requirements are higher in endurance athletes: 1.5 to 1.7 g per kilogram of weight.

But for those who practice an endurance sport in their leisure, 2 or 3 hours per week, needs do not change.
The needs of power sports (weightlifting, weight) are:
· 1 to 1.2 grams per kilogram per day when it is simply entretenirla muscle mass; daily intake of protein potions is not justified and can be dangerous because the urinary excretion of nitrogen and calcium is then greatly increased; At present, no scientific work justifies the need for any amino acid supplement.
· 2 to 3 g per kg of body weight per day when it is augmenterla muscle for periods but no greater than 6 months; these needs are met by two thirds to food, the rest from protein supplements with high biological value, or 1 g per kilogram per day.

LIPID
Intense physical activity of more than 30 minutes mobilizes reserve triglycerides in fat cells. The fatty acids are released and provide energy. It takes about 10-20 minutes for this process gets under way and take over carbohydrates.
At the same time, the fatty acid degradation releases free radicals. It is important that food is sufficiently rich in anti-oxidants.

It is not advisable for athletes to increase provided the amount of fat in their diet. The quota of 30-35% of daily calories remains valid for them as well.

CARBS

This is the most important nutrient, especially for long-term periods. Carbohydrates are energy providers immediate and longer term.
Glycogen storage carbohydrate, runs faster or slower depending on the intensity of the effort. The famous "wall of 30 km" in a marathon, which results in severe pain quadriceps, comes from carbohydrate depletion due to too fast race started.
The dissociated diet "Scandinavian" (3 days supply with 50% carbohydrate calories, and then 3 days with 70% of carbohydrate calories) is reserved for elite athletes.

A pasta meal taken between 8 and 12 hours before a competition is very useful to significantly increase glycogen stores. It is important that the meal is finished three hours before the start of the force so that the stomach is empty.

An intake of carbohydrates with high glycemic index, as ration waiting absorbed in small quantities 1 hour before the start of the activity enhances glycogen stored in the liver economy.

For all years of more than 1 hour, taking a drink rich in carbohydrates, minerals and vitamins is quite recommended. It should contain 30 to 100 g carbohydrate per liter and be absorbed into 150-300 ml every 15 to 30 minutes.
This sweet drink is also necessary after exercise. It allows resynthesis of muscle glycogen.

WATER

Muscular exercise is accompanied by loss of water, minerals and vitamins that can be significant.

Water is removed by respiration and especially perspiration.
The amounts are based on the duration and intensity of exercise.

You sweat a lot because it produces a lot of heat. The evaporation of sweat to the skin surface can eliminate this heat. Body temperature may rise to 39 or 40 ° C.

During a run, a poorly trained athlete can lose 0.5 to 1 liter of water per hour. For a marathoner high level, is 1.5 to 2.5 liters. During a football game or tennis, professional players can eliminate up to 4 or 5 liters per game.

Dehydration disrupts cardiovascular and thermal systems and reduces performance.

Dehydration of 4% of body weight is dangerous: it can promote a serious accident, sometimes fatal, as heat stroke.
Handling the weight before a competition (judo, boxing, etc) passing through sauna sessions is quite dangerous because it induces compulsory dehydration even before the competition.

It is essential to:
· Always start an exercise being well hydrated
· Do not wait until thirsty to drink during the workout; thirst occurs only when the dehydration is already 1% of body weight
· Force themselves to drink more than you feel like it: a large volume of water remains less time in the stomach and is absorbed faster by the body.

The amounts are based on the duration and intensity of exercise and ambient heat:
· 1.5 l per hour (or more) for a period of more than one hour.

Mineral water or tap water is obviously the key component of any drink.
Some nutrients may be added depending on the losses.

MINERALS AND TRACE ELEMENTS

Sodium, potassium and chlorine
These three minerals are essential for the proper functioning of the body during muscular exercise.

The usual dietary intake is usually sufficient as far beyond the needs salt and potassium.
There losses more or less important, depending on the amount of sweat.

Adding salt in the drink:
· Is not required when the exercise lasts less than an hour
· Is totally recommended beyond 1.2 g of salt per liter of water.
Potassium supplementation is needed if physical sports activity takes place in the heat:
· 1 to 2 g per day in addition to the usual requirements
· Just eat dried fruits in the day.

IRON

Iron is important in athletes for its role in the transport of oxygen by hemoglobin.
Any decrease in red blood cells is associated with decreased performance.
It is this feature that leads many athletes to absorb substances (EPO) increases the level of red blood cells.

Iron deficiency can be seen in the female athlete population, in the same proportions as in the non-sporting women. They have the same origins: inadequate dietary intake.
The iron loss through sweat during exercise are minimal.

Iron needs are not increased in athletes.
A systematic supplementation (often practiced) is not recommended because:
· It does not increase performance
· It can increase the risk of a heart attack. This danger has been evidence by some researchers.

Loss of minerals and trace elements are important enough to warrant routine supplementation in athletes. Provided of course that diet is balanced. This is not always the case. Contribution of deficiencies (iron, zinc) are seen quite often in vegetarians athletes.

VITAMINS

The need for water-soluble vitamins and fat-soluble vitamins:
· Shall not be increased in case of moderate activity and / or occasional 1-3 hours per week
· Are slightly increased in case of intense and prolonged exercise.

When power is well balanced, the quota of vitamins is satisfactory, a nutritional supplement never improves performance.
The increased production of free radicals during exercise, does not justify routine supplementation
except:
· During an activity at high altitude (over 4000 m) with strong sunlight: a supplement of vitamin E (300 to 500 mg) is useful to limit the adverse effects of oxidation.

Deficiencies may occur when caloric intake is restricted (gymnasts, dancers).
· They are always worrying because most often the growth is not complete.
It is advisable to:
· Ensure a balanced diet that naturally covers the requirements for vitamins
· Focus on foods rich in B vitamins and repeated intense exercise
· Do not swallow any further one or more vitamins: they act synergistically.