Hydration and Performance: How Much Should You Really Be Drinking During Exercise?

Staying properly hydrated is one of the most underrated performance enhancers in the gym. Whether you’re lifting weights, doing a high-intensity class, or hitting a conditioning circuit, your fluid intake plays a direct role in energy levels, focus, and recovery. This article breaks down how much you should drink based on the type of training you do — and when you might benefit from more than just water.

Why Hydration Matters in the Gym

Dehydration as little as 2% of body weight has been shown to reduce strength, power, and muscular endurance [1]. For gym-goers, that could mean fewer reps, poorer focus, and even higher risk of injury. Yet many people train without properly preparing or replenishing fluids.

General Hydration Guidelines for Gym Training

Before Training:

Aim for 400–600ml of water 2 hours before your session [2].
If you’re training first thing in the morning, rehydrate with 300–500ml on waking.

During Training:

Sip 150–250ml every 15–20 minutes during a typical 45–60-minute gym session.
This increases if you’re training in high heat, humidity, or you’re a heavy sweater.

After Training:

Weigh yourself pre- and post-session if possible. Replace each 1kg of weight lost with 1.5 litres of fluid over the next few hours.
Include sodium and electrolytes if the session was longer than 60 minutes or sweat-heavy.

Do You Need Electrolytes?

In short — sometimes, yes.

Use electrolytes when:

You’re training for 60+ minutes or back-to-back sessions.
The environment is hot or humid.
You sweat heavily or your sweat leaves white salt marks on clothing.

Electrolytes (sodium, potassium, magnesium, and chloride) support muscle function and fluid balance. Losing too many through sweat can lead to cramping, dizziness, or fatigue — even if you’re drinking water.

Good options include:

Electrolyte tablets (e.g., Precision Hydration, SIS, LMNT).
Coconut water (natural potassium source).
DIY mix: 500ml water, a pinch of salt, and a squeeze of lemon or a splash of fruit juice.

Hydration for Different Types of Exercise

Strength Training (≤60 mins):

300–600ml before.
Sip 150–250ml every 15–20 mins if warm or high-rep sets.
Post-training: Water is fine unless session was intense.

Hyrox / Circuit / MetCon Sessions (45–90 mins):

Start well-hydrated.
Include electrolytes during and after if sweating heavily.
Carbohydrate-electrolyte mixes may help if training fasted or pushing high output.

Endurance Training (90+ mins):

Drink based on sweat rate — weigh yourself before and after to personalise.
Replace sodium losses to avoid “hyponatremia” (overhydration and low blood sodium).
Include some carbohydrates (e.g., isotonic sports drinks) if performance is a goal.

Final Takeaways

✅ Don’t wait until you’re thirsty — by then, you’re already behind.
✅ Monitor your sweat rate if you’re training regularly or for performance.
✅ Electrolytes are a powerful addition, especially for longer or tougher sessions.
✅ Consistency with hydration improves recovery, gym performance, and even mental clarity.

Try this at SPC:
Bring a 750ml bottle to your next session. Drink half before you start, sip during your workout, and finish the rest afterwards. Notice the difference.