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How to Get Energy to Workout

athlete sitting exhausted on gym floor after workout due to low energy

athlete sitting exhausted on gym floor after workout due to low energy

Last updated: October 2026

If you’re dragging yourself to the gym and running out of steam halfway through, the usual advice isn’t going to fix it. Sleep more. Eat well. Manage stress. That’s not wrong — it’s just not specific enough to be useful.

Low energy during workouts almost always traces back to one of three causes: you’re not eating enough to support your training, you’re eating at the wrong time relative to your session, or you could benefit from topping up your muscles’ creatine stores for short, hard efforts. Fix the actual cause and the energy problem goes away.

This post walks through each one in order of impact.

Fix #1 — Make Sure You’re Actually Eating Enough

This is the most common and most overlooked cause of chronic low workout energy. If you’re in a calorie deficit — intentional or not — your body simply doesn’t have enough fuel to train hard. It will prioritise keeping you alive over powering your squat.

People chasing fat loss are especially vulnerable to this. They cut calories aggressively, start feeling flat and weak in the gym, and assume they need more sleep or a better pre-workout supplement. What they actually need is more food.

Your TDEE (Total Daily Energy Expenditure) is the number of calories your body needs just to maintain current weight while accounting for your activity level. If you’re consistently eating below that number, your training will suffer — regardless of what else you do.

A moderate deficit of 300–500 calories below TDEE is typically sustainable without tanking gym performance. More than that, and energy during workouts is one of the first things to go.

Are You Eating Enough to Train Hard?

Calculate your TDEE to find your daily calorie baseline. If your current intake is well below this number, low workout energy is a direct consequence — not a mystery.

Calculate Your TDEE →

Related Reading

What Happens If You Starve Yourself and Workout? (The Real Cost) →

Fix #2 — Time Your Pre-Workout Nutrition Correctly

Even if your total daily calories are adequate, eating at the wrong time relative to your workout can leave you flat. Your muscles run on glucose. If blood sugar is low when you start training, performance drops fast.

The General Guidelines

What About Intermittent Fasting?

If you’re eating in a restricted window (16:8, 18:6, etc.) and training outside that window, low energy during workouts is expected — not a sign that fasting isn’t working. The fix is either moving your training into your eating window or adjusting your fasting schedule so there’s food in your system before you train.

Optimise Your Eating Window Around Training

If you’re using intermittent fasting, the Intermittent Fasting Calculator can help you structure your eating and fasting windows so your workouts fall when fuel is available.

Plan Your Eating Window →

Fix #3 — Check Your ATP Supply (Creatine)

Creatine is not a stimulant and it won’t make you feel buzzed before a session. What it does is replenish phosphocreatine stores in your muscles, which are used to regenerate ATP — the molecule that powers short, high-intensity efforts like lifting.

Your body makes about a gram of creatine a day and you get more from meat and fish, so your stores aren’t “depleted” without supplements. But supplementing raises muscle creatine further (especially in people who eat little meat), which helps you squeeze out an extra rep or two on hard sets and recover faster between them.

Creatine monohydrate is the most researched supplement in sports science and has a strong safety profile. A standard maintenance dose is 3–5g per day. A plain tub of creatine monohydrate is enough to cover that dose. A loading phase (20g/day split across 4 doses for 5–7 days) gets stores saturated faster but isn’t required.

Find Your Creatine Dose

The Creatine Calculator gives you a personalised loading and maintenance dose based on your body weight, so you’re not guessing at the amount.

Calculate Your Creatine Dose →

Related Reading

The Complete Creatine Guide: Dosage, Timing, Side Effects, and Storage →

Fix #4 — Use Caffeine Strategically

Caffeine is the most effective legal performance stimulant available. It works by blocking adenosine receptors in the brain — adenosine is the compound that signals tiredness, so blocking it keeps you feeling alert and focused. It also has direct effects on muscle contractility and endurance.

The research-backed dose is 3–6mg per kilogram of body weight (some people benefit from as little as 2mg/kg), taken 45–60 minutes before training. For a 70 kg person that is roughly 200–400mg, and many people do well at the lower end — one or two strong coffees.

A few practical notes:

Fix #5 — Sleep Is the Foundation Everything Else Sits On

The first four fixes assume your recovery foundation is intact. If you’re consistently sleeping under 6 hours, no amount of TDEE optimisation or creatine loading will fully compensate.

During sleep, your body releases growth hormone, restores glycogen, and consolidates motor patterns from training. Athletes who sleep more generally report better energy, mood and training quality.

Practical sleep improvements that actually work:

How to Actually Wake Up Early to Workout

If mornings are the only time you can train, the problem usually isn’t willpower — it’s that you’re fighting your circadian rhythm cold, with no system to make the wake-up easier. A few changes make a bigger difference than “just get up”:

If you’re also managing low energy once you’re actually up, the caffeine timing in Fix #4 above and the sleep fundamentals in Fix #5 apply directly — a shifted wake time only works long-term if the rest of your sleep schedule shifts with it, not just the alarm.

When Low Energy Is Chronic, Not Occasional

If you’ve addressed calories, nutrient timing, creatine, caffeine, and sleep — and you’re still chronically fatigued during training — the issue may be overtraining or accumulated fatigue from too much volume with insufficient recovery.

Signs your training load is outpacing your recovery:

The fix here isn’t more stimulants — it’s a deload week (reduce volume by 40–50%) or a short break from training entirely. Recovery is when adaptation happens. Without it, training just accumulates fatigue.

The Bottom Line

Low workout energy is not a mystery and it’s not fixed by a new playlist or a fancier pre-workout. Work through the causes in order:

  1. Check your TDEE — are you eating enough?
  2. Time your pre-workout nutrition — is there fuel available when you start training?
  3. Consider creatine — would topping up muscle creatine help your hardest sets?
  4. Use caffeine at the right dose and time
  5. Protect sleep — everything else builds on this

Fix the actual cause and the energy problem solves itself.

Sources: [1] Drake C, et al. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 2013.

Dennis Kiplimo
Written by
Dennis Kiplimo

Dennis Kiplimo is a Registered Nurse and founder of Denstar Fitness. He publishes fitness calculators and writes about training, nutrition and health on Medium.

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