FIXITFIXITOpen App
Health Tracking
💧

You're Dehydrated and It's Killing Your Gains (The Science)

2% dehydration = 10-20% performance drop. Here's how much water you actually need.

5 min read May 18, 2026

The Numbers Don't Lie

A landmark study from the University of Connecticut found that just 2% dehydration (losing 2% of body weight through water loss) causes: - 10-20% decrease in strength performance - Impaired cognitive function (slower reaction times, worse coordination) - Increased perceived effort (the same weight feels heavier) - Reduced endurance (fatigue sets in 15-20% earlier) - Impaired recovery (protein synthesis drops) At 170 lbs, 2% dehydration is just 3.4 lbs of water — you can lose that in a single hard workout without replacing fluids.

How Much Water Do You Actually Need?

The "8 glasses a day" rule is outdated and not based on science. Here's the evidence-based formula: Baseline: 35ml per kg of bodyweight per day - At 77kg (170 lbs): 2,700ml = 2.7L per day Training days: Add 500-1000ml per hour of exercise - 1-hour gym session: 3.2-3.7L total Hot weather / outdoor training: Add another 500ml For most active adults in the GTA: 3L per day is a solid target. Adjust up on heavy training days. Signs you're dehydrated: Dark yellow urine, headaches, fatigue, muscle cramps, dry mouth. If you're thirsty, you're already 1-2% dehydrated.

The FIXIT Water Tracking Method

We built water tracking into FIXIT because most people have no idea how much they actually drink. How it works: 1. Open Health → Today tab 2. Tap +250ml or +500ml every time you drink 3. The progress ring fills up toward your 3L target 4. At 90%, it turns green — you're hydrated Pro tip: Set 3 anchor points: - Morning coffee → log 500ml water after - Lunch → log 500ml - Pre-workout → log 500ml - Post-workout → log 750ml - Evening → log 500ml That's 2.75L without even trying. Add a few extra glasses and you're at 3L+. The AI insights engine will flag you if hydration drops below 60% of target for 3+ days. Because your gains depend on it.
water intakehydrationgym performancedehydrationrecoveryfitness science

Ready to start training?

Track your workouts, analyze your form with AI, and crush your goals.

Get Started Free

Get FIXIT tips in your inbox

Training guides, nutrition science, and product updates. No spam.

Related Guides

📊
I Tracked Every Meal for 90 Days — Here's What Actually Happened
7 min • Health Tracking
🔄
Body Recomposition: How to Lose Fat and Gain Muscle at the Same Time
8 min • Health Tracking
🏋️
Your InBody Test Results Explained: What Every Number Actually Means
7 min • Health Tracking

We collect and process your data to provide health tracking and AI-powered exercise analysis. Your data is stored securely in Toronto, Canada.

Learn More