Section C · The Field & The Court
Tennis
Three hours of sprints in the sun with only changeovers to drink. The third set is a sodium contest.
Two to three hours of sprints and stops on a hot court with no shade. Changeovers are the only chance to drink, and most players use them for plain water or a sugar drink that sloshes.
Sugar on every changeover sloshes and spikes. A stick in cold water on the changeover goes to the legs and the hands. One before, one per hour on court, one after. Four to five for a three-set summer match. One stick in 16 oz covers a window; the schedule below covers the day.
The numbers behind tennis
Two to three hours of sprints and stops on a hot court with no shade. Changeovers are the only chance to drink, and most players use them for plain water or a sugar drink that sloshes.
Why this happens
Sweat is not just water. Every ounce carries sodium out with it, and sodium is what lets your blood hold its volume. Lose enough and there is less blood to move oxygen to working muscle, so your heart rate climbs for the same split, your core temperature drifts up, and the nerve signal that tells a muscle to relax gets noisier. That is the cramp, the dizzy stand-up and the split that will not come back, all from the same cause.
Plain water puts the volume back without the sodium, which is why it can feel like it is not working. The fix is to put back what actually left: water and the minerals that went with it, in roughly the ratio you lost them.
Tennis hides its sweat rate. Points are short, the breaks are frequent and the court has no shade, so the loss arrives in small pieces instead of one long effort. Add the sugar drink most players reach for and the stomach spends the changeover on that instead of the water. By the third set the deficit is a full session's worth, taken without ever feeling like a session.
Sugar on every changeover sloshes and spikes. A stick in cold water on the changeover goes to the legs and the hands.
The 2% line lands in the second set. The third is played past it.
At 24 to 40 ounces an hour, a 175-lb player crosses 2% somewhere in the second set. Everything the book warns about, the hand cramp, the double faults, the bad call on the big point, sits on the far side of that line.
Three sets is 72–120 oz out. Heavy sweaters cross the 2% line (56 oz for a 175-lb player) early in the second set; everyone else by the start of the third.
One stick an hour in the changeover bottle is 1,800 mg over three sets, which stays ahead of the 1,500 mg going out.
What you get back when you stay ahead of it
Decisions go first when the focus fades late. Staying under 2% is the cheapest thing you can do for the choice on the big point in the third set.
The Hydration PlaybookHand and calf cramps in hot-weather tennis track with heavy, salty sweat losses. Sodium back in at each changeover is the fix; plain water on its own does not stop it.
Bergeron, J Sci Med Sport, 2003Endurance goes before strength. Stay ahead of the loss and the first step in the third set is the one you had in the first.
Savoie et al., Sports Medicine, 2015Two matches in a day becomes normal once the deficit stops carrying over from the morning match to the afternoon one.
The Hydration Playbook
Dry, then hydrated, piece by piece
The red panel is what is happening now. The green one is what the next section buys you, and roughly how long each part takes to show up.
- Coffee and no water before the first serve
- Sun on the court from the warm-up
- Skipped the first changeovers because you were up a break
- Heart rate climbs for the same rallies
- A sugar drink sloshes for three games
- Decisions get worse on the big points
- Cramps in the calves or the racket hand
- Serve speed drops; double faults climb
- Headache after a summer match
What to drink, and when
Start with during. It is the window most people in tennis get wrong. For a normal training day rather than a race, the timing guide covers every window.
BEFORE
- 16 oz with a stick at T-90
- 8 oz plain water in warm-up
Start full so the first set spends what you have.
DURING
- 4–6 oz of a mixed bottle at every changeover
- One stick per hour; two in the heat
Replaces the sodium going out so the third set has legs and the hand does not cramp.
AFTER
- 24 oz per pound lost
- A real meal
Sets up the second match or the drive home.
The book's tennis number: every pound lost is 24 oz to put back within the hour, then a real meal. Weigh in before the warm-up and out after the match.
What to take, and what we do not sell
Two of these three are things we do not sell. A hydration stick does not fix fuelling, and pretending otherwise is how people end up disappointed.
Electrolytes
Fuel
Worth taking too
The questions we get about tennis
How much do you sweat in tennis?
24–40 oz of sweat an hour on a summer court. 1,500+ mg of sodium out over a three-set match. Weigh in before and out after a session: every pound down is about 16 oz you did not put back.
When should I drink during tennis?
Every changeover: 4–6 oz of a mixed bottle at every changeover; One stick per hour; two in the heat. Replaces the sodium going out so the third set has legs and the hand does not cramp.
What should I drink before tennis?
T-90 to the first serve: 16 oz with a stick at T-90; 8 oz plain water in warm-up. Start full so the first set spends what you have.
How do I recover after tennis?
Within the hour: 24 oz per pound lost; A real meal. Sets up the second match or the drive home.
Do I need electrolytes or is water enough?
Water replaces the volume you sweat out but not the sodium, potassium and magnesium that left with it, and without sodium your body cannot hold the water. Per hour of hard work: Sodium 500–700 mg, Potassium 150–300 mg, Magnesium 30–60 mg, Water 16–24 oz.
How many sticks do I need?
One before, one per hour on court, one after. Four to five for a three-set summer match. Two bottles courtside, both mixed, and drink on every changeover whether you are thirsty or not. Thirst arrives a set late.
Why do my hands cramp in the third set?
Hours of sweat took sodium with it and the changeovers put back water without it. The signal to the forearm gets noisy and the grip locks up. A stick an hour in the changeover bottle is the version of this that does not happen (Bergeron, 2003, on tennis heat cramps).
Is a sports drink better than water for tennis?
Plain water puts back volume without the sodium. A sugar drink puts the stomach to work in the middle of a changeover. A stick in 16 oz keeps the minerals coming without the sugar load; the fuel for the match is in the fuel column above.
How much should I drink in a three-hour match?
The book puts it at 24 to 40 oz an hour, so 72 to 120 oz across three sets, most of it at changeovers, with one stick an hour to keep the sodium in step. Weigh in before and after the first hot match of the season and you will know which end of that range you sit on.
Everything in the box
The book this article came from is in there too. One page for every sport, so the next thing you take up is already covered.
Five flavours, one stick each
Taste is the only part of this you cannot take our word for. The starter kit gets you all five so you find the one you will actually reach for at minute four, not the one that sounded good online.
- All five minerals sweat costs you, no sugar.
- Informed Sport certified, batch by batch.
- Mixes into whatever bottle is already on the courtside bench.
