Sweating it out: Why crucial vitamins need replacing after exercise

Post Workout

An average person sweats between 0.8 to 1.4 litres of fluid per hour of exercise. Most endurance athletes might already be aware of the crucial vitamins they lose through sweat, but many non-competitive athletes may think it’s only water (and salt) they’re excreting through their pores.

Whether your patients are casual or professional athletes, it’s always good practice to remind them how important it is to replace water soluble vitamins like C and the range of Bs that their sweat carries out during intense training. Here are some ways to help your athletic patients restore important nutrients post-workout.

B vitamins play a role as coenzymes in the energy production of cells. Exercise appears to especially increase the loss of thiamin, riboflavin and vitamin B6. In fact, the body might need to take in twice the daily recommended amount of these vitamins to replace what the body sweats out through exertion.

In vitamin C’s case, multiple studies have found blood and plasma levels of vitamin C to be lower in those who exercise, since stores are used to combat exercise induced oxidation in muscles and other cells, which is brought on by physical activity. Vitamin C also plays an important role in muscle growth, as it’s essential for building collagen, the connective tissue that helps repair tissues and tendons.

Research shows that vitamin C may even help reduce post-exercise pain and inflammation due to it’s ability to help repair the tiny tears in our muscle fibres that can result in muscle soreness and pain after workouts. Proper vitamin C supplementation both pre and post workout can be effective in helping prevent deficiencies and promote faster muscle recovery.

Although there is evidence that exercise increases the demand for these vitamins, supplementation does not appear to have an enhancing or ergogenic effect.

The general consensus among sports nutritionists is that most athletes and active individuals would be able to meet these increased nutrient demands by eating a balanced diet.

Individuals at greatest risk for exercise induced vitamin deficiency are those following a low-fat or low-calorie diet, and those who don’t eat enough fruits, vegetables and whole grains. In these individuals supplementation of the above key nutrients to prevent deficiency is crucial.

Vitamins lost in sweat

Food Scale
How to determine sweat loss and proper rehydration

  1. Measure body weight both before and after at least one hour of exercise under conditions similar to a competition or hard practice.
  2. The difference between your pre and post-workout body mass measurement is your fluid loss. ex:
    Pre-exercise weight =74.5kg
    Post-exercise weight = 72.8kg
    Fluid deficit = 1.7kg
  3. Estimate the weight of any fluid or foods you have consumed during the workout. ex. 800ml of fluid = 800g
  4. Sweat loss = body mass before exercise (in kg) – body mass after exercise (kg) + weight of fluids/foods consumed (kg).
    ex. 74.5-72.8 = 1.7kg deficit + 80kg = 2.5kg of sweat loss
  5. The total amount of sweat or fluid loss will be a gauge as to how well you hydrated during the session and how much you need to rehydrate afterwards.