Regular water intake and good hydration are incredibly important for your body to work at its best and for you to maintain your health and well-being. The harmful effects of dehydration start when your body’s fluid levels are only a small amount below the ideal, and the lower the level the more severe the physiological effects that you may experience. This becomes increasingly important when you are exerting yourself physically through exercise.

Effects of dehydration and physical exercise

As an example, being as little as 2% dehydrated will cause you to become thirsty and lead to increased heart rate and breathing when exercising compared to normal. You body will be less effective at sweating and managing the core and muscle temperature increases that you experience during exercise. Allowing dehydration to continue unchecked especially when exercising in warmer climates can lead to nausea and dangers such as heat stroke.

So whether you are training for a sport or perhaps running to lose weight it is important to keep check on your hydration levels to stay safe and make sure that you are getting the most benefit from your exercise session.

Dehydration and weight loss

When trying to losing weight whether diet or exercise alone or through a combination, the goal is typically to cut body fat. Dehydration has a negative effect on weight loss by lowering your metabolism and reducing the rate at which the body can burn fat during exercise. So staying well hydrated is one of the most important things that you can do to lose weight.

Keeping dehydration in check

See how dehydrated your are a few times each day by simply taking note of the colour of you urine as follows:

  • Clear or light straw coloured urine - you are well hydrated
  • Light Yellow urine - you are mildly/moderately dehydrated
  • Orange, amber or brown urine - severely dehydrated
Note that taking vitamin supplements can change your urine colour for a few hours.

You may already have noticed that your urine is regularly yellow or orange meaning that, like many people you are chronically dehydrated and need to change you habits to compensate.

Beating dehydration


If you are severely dehydrated then you should consider seeking advice from a health professional. However, dehydration treatment is quite simple when you know some hydration basics and the problem is only mild to moderate. Simply start drinking small amounts of water regularly throughout the day aiming to drink a few litres of water over the course of the day. As you body can only re-hydrate at a certain rate, absorbing anywhere between 400-800ml per hour depending on a range of factors, it is important to drink regularly over the course of the day. 

When this is working you should find yourself passing clear or light coloured urine more often. When you arrive at your training session or on the sports field, you will already be well hydrated, perform at your best and burn more fat during your exercise, something drinking of water just ahead of exercise just cannot do.