Vitamin and Mineral Loss in Hot Weather and when Exercising

Vitamin and Mineral Loss in Hot Weather and when Exercising

As most of us enjoy the unusually hot weather in the UK it is a good time to reflect on how certain vitamin and mineral levels in our body can be adversely affected by heat. A lot of us take the opportunity of such good weather to walk, cycle and play sports. And it’s interesting that studies into the potential loss of certain vitamins and minerals in hot weather are often focused on those undergoing rigorous physical exercise such as sportsman (particularly distance cyclists and runners) and military personnel.

Of course first and foremost we need to try and avoid getting too much sun, protect our skin with a suitable SPF, protect our eyes with sunglasses and keep good hydration with plenty of water and natural juice drinks (and not alcohol nor lots of fizzy or caffeinated drinks).

The heat makes us sweat more and this will affect our levels of water soluble vitamins. The water soluble vitamins are the B-Complex vitamins and vitamin C. Water soluble vitamins are stored in relatively small amounts in our body and cannot be retained for long periods. They are lost through sweat and excretion and hence need regular replacement in the body. Conversely fat-soluble vitamins are stored in our liver and fatty tissues, and are eliminated much more slowly.

A range of diverse studies seem to demonstrate that people suffering from heat exhaustion (or heat stroke) are almost always deficient in vitamin C. So good levels of vitamin C may firstly help reduce the severity of hot weather exposure and robust exercise; secondly poor levels of Vitamin C may exacerbate such episodes of heat and exercise and thirdly a good Vitamin C intake from a suitable source is likely to help speed recovery after heat exposure or exercise.

Indeed Vitamin C has a number of ‘proven’ scientific health claims (from EFSA the European Food Safety Authority) and these include contributing to:

  • Protection of DNA, proteins & lipids from oxidative damage
  • Normal function of the nervous system
  • Nomal energy yielding metabolism
  • Maintenance of normal function of the immune system during and after extreme physical activity

Hence Vitamin C rich drinks, supplements or foods (such as fruits) are popular with athletes who need regular intake of vitamins to replace losses after physical exertion.

B-Complex Vitamins are necessary for the normal functioning of the nervous system and may be the single most important factor in the maintenance of the nerves. The water solubility of the B-Complex vitamins means that any excess is excreted and not stored; therefore they must be continually replaced.

Stress and excess alcohol consumption (for example) place a greater burden on our B-Vitamin supply, quite literally ‘burning’ up our reserves. Similarly high B-Vitamin loss due to excess sweating or heat exposure could lead to physical and neurological problems. Pantothenic Acid (Vitamin B5) for example provides a role in contributing to:

  • Normal mental performance
  • Normal energy yielding metabolism
  • Reduction of tiredness and fatigue

Minerals do not have the same ‘classification’ as vitamins in respect of being water or fat soluble. Indeed Mineral absorption and uptake is very different from vitamins and each mineral has its own properties in these respects.

The minerals most commonly identified as suffering significant losses in sweat due to rigorous exercise or overexposure to heat would be: zinc, magnesium, calcium, sodium and potassium. The main source of sodium is of course salt and hopefully we are all aware that excess salt consumption is very bad long-term for us humans. However severe sodium loss due to a prolonged bout of diarhhoea (for example) may mean that a little salt added to water and lemon juice (for vitamin C loss) is recommended.

Zinc is the second most abundant trace mineral in the body, being present in all tissues. Zinc has a wide variety of functions including growth and human development, the healthy functioning of the immune system, and the maintenance of healthy skin, hair, nails and bone. It is related to the normal absorption and action of vitamins, especially the B-Complex.

Zinc is readily absorbed in the upper and small intestine. The body only absorbs as much as it needs at a time; the rest is unabsorbed and about 6mg is lost daily. Too much fibre will not allow zinc to be used because it binds and carries zinc away before it can be accepted by the absorption sites. The largest store of zinc occurs in the liver, pancreas, kidney and bones and voluntary muscles.

Magnesium is an essential mineral that accounts for about 0.05% of the body’s total weight; nearly 70% of the body’s supply is located in the bones. Some 30%-40% of ingested dietary magnesium is absorbed, while the rest is excreted in the faeces.

Magnesium is involved in many essential metabolic processes, including the release of energy from glucose and the synthesis of protein and nucleic acids. Most magnesium is found inside the cell, where it activates enzymes necessary for the metabolism of carbohydrates and amino acids. It also regulates the acid/alkali balance in the body and is necessary for proper functioning of muscles.

Magnesium is absorbed in the small intestine. The rate of absorption is influenced by the parathyroid hormones, the rate of water absorption and the amounts of calcium, phosphorus and lactose in the body. Both magnesium and calcium compete for the same absorption sites. Absorption may be inhibited by other foods and Vitamin D is necessary for the proper utilisation of magnesium.

We can see how important good levels of both the minerals Magnesium and Zinc are to our health. They are two minerals whose levels are influenced by sweat loss and frequently cited in research on athletes who are regularly deficient.

A good multivitamin and mineral will help all family members throughout the year even in the best of weather when optimism and health seem at their highest. A good formula will elevate the nutritional status of people eating average to good diets to optimum levels and it will also elevate the nutritional status of those eating poor diets to an improved level of nourishment and protection.

So in the context of this article we would suggest a formula that has good levels of Vitamin C and B-Complex vitamins, plus other vitamins and a range of minerals – all suited to the individual based on their age, sex and health.

As always when considering taking any supplement the comment above “all suited to the individual based on their age, sex and health” is extremely important. So for example a man is most unlikely to want a multivitamin with Iron, nor a post-menopausal woman; in fact this could be quite harmful to health for such groups. Other common cautions, for example, when looking at multivitamins and minerals are vitamin A levels and women and calcium levels and men.

We would always stress that everybody seeks suitable and qualified advice when looking at purchasing a food supplement – the right advice is very much based on each individual.

If you have any questions regarding this article or any other health matters please do contact me (Amanda) by phone or email at any time. I can also put you in touch with a nutritional practitioner in your area.

Amanda Williams
01684 310099

Last updated on 15th December 2014 by


14 thoughts on “Vitamin and Mineral Loss in Hot Weather and when Exercising

  1. Hello, I’m very curious about something I noticed in my sweat, particularly in my thighs, after a spinning class. When I take a shower after, I notice that my sweat is noticeable viscous, gives me a ‘gel’ like feeling when I wet my legs. Why does it happen? Am I excreting something specific through my sweat? What could be affecting the viscosity of my sweat? I researched a lot about this but couldn’t come up with an answer. Thanks in advance!

    1. Hi Tames,

      At this point I can only suggest that you might be slightly dehydrated which can give rise to more concentrated sweat, or that you may have a sodium/chloride imbalance that is causing this. However, a sodium/chloride imbalance does not usually have a sudden onset later in life nor does it only happen at certain times – so unfortunately at this point I don’t have a definitive answer for you. I would be interested to hear about the other research then I might be able to look into it further.

      If you need any further assistance please do e-mail me at

      All the best,

      1. Bicycle shorts+ fabric softener+ high ph. Sweat is my guess. Do this enough = rash that you have no idea where it came from.

  2. Hi,

    I have lost 16 kg in 3 month. After that whenever i do workout, i sweat & feel cold smtm. Even if the weather is warn i feel cold smtm. I also face sm muscle small pain as well. I just started taking a multi vitamin multi mineral supplement

    1. Dear Ranbir,
      This is quite a significant amount of weight loss in a short period of time. You do not mention whether it was intentional or whether you are now underweight? Any unexplained weight loss should be investigated by your GP. You also mention feeling cold and muscle pain. I recommend that you visit your GP to discuss these symptoms as well. We do offer a free health questionnaire service and can provide you with some written diet and supplement recommendations to support your health goals if you complete this and return it to us. However, this is not a substitute for medical advice.
      Kind regards,

  3. I’d like to know if there is a soluble multi vit/mineral replacement supplement that i can take after intense running and sweating, not just water. thanks Robert

    1. Hi Robert, thanks for your question on our blog. I think you are looking for an electrolyte replacement supplement which will include potassium, magnesium, chloride and sodium – it is not a product we sell. If you add that to google as a search term you should be able to find one. In addition you might want to consider an all-round multivitamin and mineral supplement – the one I would recommend is CoQ10 Multi – you can take one or two capsules per day. Do take this with food – with either breakfast or lunch. Some sports people also take extra magnesium – in which case Biofood Magnesium after exercise. Finally if you find the intense exercise has negative effects on your gut, you might like to consider a live bacteria supplement. Thanks Clare.

  4. Hello,
    I’m seeking advice for my husband, age 57. His job has him doing physical labor in extreme heat and sun. He’s already a perspires a lot, but he has atrial fibrillation which increases his sweating dramatically. While working, he tries to remain hydrated by constantly consuming water and sports drinks. But, he’s suffering regularly from cramps, fatigue and exhaustion. I’ve got to start him on the proper supplements to help him replenish himself, but I am unsure what those should be in addition to an age appropriate men’s multivitamin. Any suggestions would be much appreciated. Thank you. Lacy

    1. Dear Lacy,

      Thanks for your question. In this heat as well as keeping hydrated with water it is important to ensure adequate intake of electrolytes – sodium, potassium, magnesium and calcium. So some good quality salt eg Himalayan salt or sea salt (avoid table salt) on a daily basis will provide you some sodium. However, too much salt is not a good idea so this would depend on what he is eating in his diet.

      He may also like to supplement with magnesium. For example Biofood Magnesium. Low levels of magnesium can be a cause of cramping. If your husband is taking blood pressure medication then please let us know.

      With regard to potassium I suggest that he increases his intake of vegetables and fruit which are good sources.

      Alternatively, he could also consider an electrolyte replacement supplement which contain sodium, chloride, magnesium and potassium. See the previous comment on this blog. Sports drinks tend to be high in sugar (or artificial sweeteners) so plain water is best for staying hydrated and an electrolyte replacement supplement can be added.

      Low calcium levels can also be a cause of cramps. However, I would try the other recommendations first. If after a week or two there is no improvement then some short term calcium supplementation could be considered. However, calcium is not something I would recommend supplementing long-term unless it is really needed (eg for people with diagnosis or risk of osteoporosis or low dietary intake etc) as it can be deposited in soft tissue and most people obtain an adequate amount from their diet. Magnesium on the other hand can be low in many people’s diets.

      As you husband has a diagnosis of atrial fibrillation I would also suggest that he visits his GP and discusses his symptoms.

      Your husband may also be interested in our free health questionnaire service. If he complete a copy of our health questionnaire and returns via email, we will send some written diet and supplement recommendations.

      We can also check interactions with any medications your husband may be taking.

      I hope this helps.

      All the best,

  5. Hi, I’m 56 yrs old, I had a mini stroke 11/2 yrs ago and am on blood pressure tablets, blood thinning and statins. I sweat an unbelievable amount, so as where sweat literally drips off me. I am always very very tired and wondered if , because of the sweating it is causing fatigue. No matter how much sleep I seem to get, I am always tired

    1. Dear Maree,

      Thank you for your question on our blog. There can be a number of reasons for excessive sweating and if you haven’t visited your GP about this then I recommend that you do so in order that any appropriate investigations can be undertaken and underlying health conditions identified.

      It is possible that excessive sweating is leading to dehydration and this can cause fatigue and when you sweat you will lose both electrolytes as well as water – so both need to be replaced. If you are avoiding salt because of your blood pressure you may want to add a pinch of good quality Himalayan salt to your food. Again when you visit the GP mention the fatigue as well so he can investigate other causes (for example anaemia or others).

      In the meantime I would suggest taking a good quality multivitamin and mineral e.g. CoQ10 Multi – start with 1 per day for 7 days and then increase to 2 per day. This is an all round multivitamin and mineral with good levels of B vitamins for energy. If however you are found to be anaemic then you would need additional iron as this is a low iron formula suitable in particular for post-menopausal women and men.

      In addition you may be interested in our free health questionnaire service – if you complete and return a health questionnaire we will send you some diet and supplement recommendations to support your health goals.


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