How to Hydrate during Exercise

Oranges, lemons, agave and salt

Ingre­di­ents for Cit­rus Quencher

How hydrat­ed you are dur­ing long runs or bike rides can deter­mine if you will thrive or with­er dur­ing your exer­cise ses­sion.

Exer­cise caus­es your body tem­per­a­ture to increase, the extent to which depends on your exer­cise inten­si­ty, exer­cise dura­tion, the cli­mate, the clothes you are wear­ing and your meta­bol­ic rate.  In order to cool your body and low­er your body tem­per­a­ture, your body begins to sweat.  This sweat is made up of water and elec­trolytes.

Elec­trolytes, such as sodi­um, potas­si­um, chlo­ride, mag­ne­sium and cal­ci­um, are min­er­als that car­ry elec­tri­cal charge, which are essen­tial for reg­u­lat­ing flu­id bal­ance, mus­cle con­trac­tion, nerve func­tion and acid base bal­ance.

When you are not ade­quate­ly hydrat­ed when exer­cis­ing, you become dehy­drat­ed.  Exer­cis­ing in a dehy­drat­ed state can impact your per­for­mance and/or health in a bad way.

Dehy­dra­tion can lead to:

  • increased heart rate
  • loss of coör­di­na­tion
  • com­pro­mised men­tal con­cen­tra­tion
  • mus­cle fatigue
  • inabil­i­ty to reg­u­late body tem­per­a­ture
  • heat ill­ness, such as cramps, heat exhaus­tion or heat stroke
  • decreased ener­gy and ath­let­ic per­for­mance
  • increased risk of gas­troin­testi­nal upset

Don’t rely on your thirst mech­a­nism to deter­mine if you are ade­quate­ly hydrat­ed;  once you feel thirsty, you may already be dehy­drat­ed.

There are two ways you can deter­mine if you are ade­quate­ly hydrat­ed:

1. Body weight before and after exer­cise

2. Urine col­or


1. Body weight before and after exer­cise

You can deter­mine your sweat loss by weigh­ing your­self before and after exer­cise.  Weigh your­self in the nude, then sub­tract your post-train­ing weight from your pre-train­ing weight.

Any weight lost is like­ly due to flu­id loss­es. The table below can help iden­ti­fy hydra­tion sta­tus:

%Body Weight Change

Well Hydrat­ed -1 to +1%
Min­i­mal Dehy­dra­tion -1 to -3%
Sig­nif­i­cant Dehy­dra­tion -3 to -5%
Seri­ous Dehy­dra­tion -5%

A weight loss of greater than 1% indi­cates mild dehy­dra­tion and a weight loss of greater than %5 indi­cates seri­ous dehy­dra­tion.  Replen­ish with about three cups of flu­id per pound lost.

2. Urine col­or

The sec­ond, and eas­i­est way to deter­mine if you are ade­quate­ly hydrat­ed,  is by check­ing the col­or of your urine.  A very light col­or of urine (think lemon­ade) means you are well hydrat­ed. The dark­er the urine (think apple juice)  the more dehy­drat­ed you are.

On the oth­er hand, an increase in weight means you are over-hydrat­ed.  Drink­ing too much water can lead to hypona­trem­ia.  Hypona­trem­ia indi­cates an excess of water in rela­tion to the amount of salt in your body. This can lead to seri­ous med­ical con­di­tions and even death.

What to drink?

Although water is the first and best choice when hydrat­ing dur­ing an exer­cise ses­sion, there are times when a sports drink can be ben­e­fi­cial.  Stud­ies show that when you are exer­cis­ing at high inten­si­ty for 45–75 min­utes, small amounts of a sports drink, even a mouth rinse, can improve your exer­cise per­for­mance.  It seems to be only effec­tive then you are exer­cis­ing in a fast­ed state, such as an ear­ly morn­ing exer­cis­er, when exer­cis­ing sev­er­al hours after eat­ing or when you are not get­ting enough car­bo­hy­drates in your diet in gen­er­al.

For exer­cise ses­sions that last 1–2.5 hours, get­ting 30–60g of car­bo­hy­drates per hour, has been found to be ben­e­fi­cial. Choose a sports­drink with a car­bo­hy­drate con­cen­tra­tion of 6–8% and sodi­um of 460 to 690 mg/L. In oth­er words an 8 oz serv­ing or one cup should con­tain about 15 g car­bo­hy­drates and 110–165mg of sodi­um.

Ultra endurance exer­cise ses­sions of >2.5–3hours can ben­e­fit from up to 80–90 g car­bo­hy­drates per hour.

In addi­tion, recent stud­ies show that a car­bo­hy­drate mix­ture of glu­cose and fruc­tose increas­es absorp­tion of car­bo­hy­drates and in turn increas­es per­for­mance.

If you pre­fer fresh nat­ur­al ingre­di­ents or are tired of the same sports drink, try mak­ing one your­self.  See my recipe below to help get you start­ed.  The ide­al car­bo­hy­drate con­cen­tra­tion should range from 6–8%.

Cit­rus Quencher

Makes one quart.


14 cup agave syrup

14 tea­spoon salt

14 cup water

14 cup orange juice plus 2 table­spoons lemon juice

12 cups cold water


1. Add ingre­di­ents to a large pitch­er and stir.  Chill for sev­er­al hours for most refresh­ing taste.






  1. Homemade Sports Drink | Uncanny - [...] Ray emailed the following recipe to me, so I thought I’d share it with you. He found it on…

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