You finish your workout, feel great, and then… boom. An hour later you’re on the couch, exhausted, starving, or feeling like you need a nap. This happens because your body burns through energy and resources during exercise, and several factors can leave you feeling drained afterwards.
What causes post-workout crashes?
Your body needs fuel, water, and recovery time after exercise. When you don’t give it these things, you crash. Your blood sugar drops, your glycogen stores run low, your body gets dehydrated, and your muscles need time to repair themselves.
Research shows that exercise depletes your glycogen stores, which are your body’s main energy source during workouts. When these stores run low and you don’t refill them, your energy tanks and you feel exhausted.
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Does eating before a workout prevent crashes?
Yes. Eating a combination of protein and carbs about 30 minutes to an hour before your workout can stop crashes before they start. Your body needs carbs for energy during the workout and protein to protect your muscles.
Think of carbs as your body’s preferred fuel source. Without them, you’re running on empty. Studies show that people who eat before working out perform better and recover faster than those who train fasted.
What should I eat after working out to avoid crashing?
Eat protein and carbs within an hour of finishing your workout. Aim for at least 20 grams of protein. This helps your muscles recover and refills your energy stores.
Your post-workout meal matters more than your pre-workout meal for beginners. Once you’re more experienced, you can be more flexible. What you eat throughout the entire day makes the biggest difference, but that post-workout window helps your body bounce back faster.
Good options include chicken with rice, Greek yogurt with fruit, or a protein shake with a banana.
Can dehydration cause post-workout crashes?
Yes. Your body loses water through sweat during exercise, and even small amounts of dehydration can make you feel tired, weak, and foggy. Water helps transport nutrients to your muscles and removes waste products that build up during workouts.
Drink water before, during, and after your workout. A good rule is 2 to 3 litres per day for most people, more if you’re sweating a lot. If you’re thirsty, you’re already dehydrated.
Does working out too long cause crashes?
Absolutely. Training for more than 60 minutes starts to increase cortisol levels, which can hurt your recovery and make you feel wiped out. Cortisol is a stress hormone that rises during long workouts and can leave you feeling exhausted.
Most people should aim for 50 to 60 minutes of actual work after a 10 minute warmup. Past that point, you’re fighting against yourself. Keep your workouts focused and intense rather than long and dragging.
Can poor sleep make me crash after workouts?
Yes. Sleep is when your body recovers and rebuilds. Bad sleep means bad recovery, which means you’ll feel terrible after workouts. Studies show that people who sleep poorly are more likely to get sick after training, which keeps them from working out for days.
If you’ve slept badly, consider skipping your workout and focusing on recovery instead. One missed workout is better than getting sick and missing a whole week. Aim for 7 to 8 hours of good quality sleep each night.
You can also try a 10 to 60 minute non-sleep deep rest session if you’re short on sleep but really want to train. These sessions help restore your ability to do mental and physical work, even if you don’t fall asleep during them.
Does cardio cause more crashes than strength training?
It depends on how much you do. Cardio can actually suppress your appetite in the short term, but long cardio sessions can tank your energy for the rest of the day. People often move less after doing cardio, which is called NEAT or non-exercise activity thermogenesis.
Walking is better than intense cardio for most people because it doesn’t leave you exhausted. You can walk for 7,000 to 12,000 steps per day without crashing, and it burns calories without making you so tired that you sit on the couch for the rest of the day.
Can eating too little cause workout crashes?
Yes. If you’re eating in a calorie deficit and training hard, your body runs out of energy fast. You need to eat enough to support your workouts and recovery. Most people should lose no more than 0.5 to 1 percent of their body weight per week when dieting.
Going lower than that can crash your metabolism and make you feel terrible after workouts. Protein helps here too, because it burns 20 to 30 percent of its calories just through digestion, which means it gives you more sustained energy than carbs or fats.
How much protein do I need to avoid crashing?
Multiply your body weight in pounds by 0.8. If you weigh 200 pounds, you need about 160 grams of protein per day. If you use kilograms, multiply by 1.8 instead.
Protein helps you build muscle, recover faster, and feel fuller longer. Studies show that going from a low protein diet to a high protein diet can increase your daily calorie burn by 4 to 5 percent, which is like doing a 10 minute jog every day.
FAQ
Q: How soon after a workout will I feel a crash?
A: Most people crash 30 minutes to 2 hours after finishing their workout, depending on what they ate, how hard they trained, and how hydrated they are.
Q: Will caffeine before a workout prevent crashes?
A: Caffeine can help during your workout, but it won’t prevent a crash if you’re dehydrated or haven’t eaten enough. It’s a temporary fix, not a solution.
Q: Can I prevent crashes by eating during my workout?
A: For workouts under an hour, you don’t need to eat during training. If you’re training longer than that, a quick source of carbs like a banana or sports drink can help.
Q: Does age affect post-workout crashes?
A: Yes. As you get older, your body takes longer to recover, which can make crashes feel worse. Prioritise sleep, nutrition, and recovery time even more as you age.
Q: Should I work out if I know I’ll crash afterwards?
A: Fix the cause first. Eat before and after your workout, drink water, keep your sessions under 60 minutes, and get enough sleep. If you do those things, you won’t crash.
