Hydration

Hydration: what is it?

Hydration is the least interesting subject in nutrition and one of the most frequently neglected. Clients who track every gram of protein routinely train dehydrated, and it costs them session quality they blame on sleep or motivation. It is also one of the easiest habits to build, which makes it good early-win territory for a coach setting up a new client.

How much fluid a client needs

The familiar two litres a day is a rough starting point rather than a requirement, and it ignores body size, climate, training and diet. A 95 kg client training in a hot gym has a very different need from a 55 kg client working in an air-conditioned office.

Common practice is to scale intake to bodyweight and then add for training and heat. Food contributes as well, especially a diet high in fruit and vegetables, so total fluid intake is not the same as what comes out of a bottle.

Signs a client is under-hydrated

Thirst is a late signal, not an early one. More useful markers are urine colour through the day, headaches in the afternoon, unusual fatigue in sessions that should be routine, and a client who reports feeling flat without any change in training or sleep.

Bodyweight can also mislead. A morning weigh-in after a hot night or a hard session can drop a kilo purely from fluid, and a client who reads that as fat loss will be confused when it returns the next day. This is another reason to coach the weekly average rather than the daily number.

• Pale straw urine through the day is the simplest practical check.
• Thirst arrives after the performance cost, not before it.
• A bottle on the desk beats any reminder app.
• Coffee and tea count toward daily fluid; they are not a net loss.

Building the habit

Hydration fails as a target and works as a habit. Telling a client to drink three litres produces nothing; attaching the drinking to something they already do every day produces results. A bottle filled at the same moment each morning, a glass before every meal, a bottle in the car.

It is also worth setting a realistic starting point. A client currently drinking under a litre a day will not jump to three, and pushing it produces a fortnight of running to the toilet and then abandonment. Raise it in steps, the same way you would raise fiber.

Where it stops being a coaching matter

Drinking far too much water too quickly can dilute blood sodium, which is a genuine medical risk in endurance events, not a theoretical one. The practical rule for a coach is that fluid recommendations scale with sweat loss, and that huge volumes without sodium are not safer than moderate volumes.

Persistent thirst, very frequent urination or unexplained changes in fluid need are medical signals, not coaching problems. Refer.