If you often find yourself feeling shaky after a workout, the problem may arise from poor breathing technique, eating and hydration habits, or your training schedule. Making simple adjustments in these areas will often resolve the issue. However, you should consult a doctor if the problems worsen, the fatigue becomes overwhelming or your urine becomes dark-colored.
Weakness after exercise can come from restricted breathing, improper hydration or nutrition, failing to cool down or inadequate rest between workouts. Pay attention to these areas of your workout practice to find the solution for you.
Practice Proper Breathing
If you don't breathe fully, you can't deliver the oxygenated blood that your brain and muscles need to perform effectively. This can happen when you restrain your breath while working out. For example, you might focus on tightening your core muscles and "forget" to inhale and exhale complete breaths. This can leave you feeling dizzy, weak or lightheaded.
If this happens after a workout, you should sit down and spend three to five minutes taking three deep breaths at a time. Exhale completely before taking the next breath. When you feel better, you can slowly get up and resume a standing position.
Eat Right and Hydrate Properly
Your body needs sufficient water and the right kind of food to have a successful workout and feel good afterwards. Lack of water leads to dehydration during exercise, while exercising on an empty stomach can cause a sudden drop in blood sugar. Either one or both can leave you with feelings of weakness after exercise.
Exercise raises your body temperature, so you naturally sweat to cool yourself. If you don't replace the water lost through sweating, you can become dehydrated.
As you exercise, your muscles burn more glucose than normal because they need the energy. As the glucose in your bloodstream is used up, your brain may become starved of the glucose it needs, leading to feelings of of being dizzy, confused, headachy or fatigued.
Preventing dehydration and low blood sugar means paying attention to what you eat and drink — before, during and after you exercise. You need a diet that balances complex carbs, veggies, fruits and proteins to fuel your muscles.
To help balance your food and water needs with your exercise program, you can:
- Eat a snack or light meal one to two hours before you exercise.
- Eat again within an hour after you finish your workout.
- Drink water throughout the day, averaging 10 to 12 eight-ounce glasses.
- Drink water or sports drinks at intervals during your workout to replace fluids and electrolytes lost through sweating.
Take Time to Cool Down
Cooling down is more than a nice finishing touch. Done properly, it can help prevent a sudden drop in blood pressure that could leave you feeling weak after a workout.
During active exercise, your heart pumps faster, pushing more blood to the arm and leg muscles, while blood vessels close to the skin surface dilate to help dissipate heat. If you suddenly stop exercising, your heart rate falls but the blood may remain in the expanded blood vessels, reducing the amount of oxygenated blood pumped from the heart to the brain. When your brain doesn't get enough oxygen, you feel dizzy or lightheaded — sometimes enough to faint.
You can prevent this by taking 10 minutes to gradually taper your activity level near the end of your exercise session. Spend a few minutes continuing your activity at a slower pace, then a few minutes at a low-level activity like walking. Finish with several minutes of stretching.
Rest Between Workouts
Resting between workouts is as important as the exercise periods themselves. Muscles need time to rebuild and grow before going back for the next workout. Feeling fatigued is a sign that you haven't completed your recovery. During this time, do low-impact activities until you feel rested enough to go back to your training schedule.
Consistently pushing yourself beyond your limits can lead to overtraining syndrome, which is characterized by:
- Declining performance
- Mood swings
- Increased risk of injury
- Detrimental metabolic changes
In many cases, you can prevent overtraining by getting proper nutrition and taking rest days. You may benefit from professional help to establish and maintain a training schedule that works for you. You should also seek medical help if symptoms of weakness, fatigue, or dizziness occur during exercise, or if your post-workout symptoms don't go away after making reasonable adjustments to your routine.
- Healthline: What Causes Dizziness After a Workout?
- American Council on Exercise: Nine Signs of Overtraining
- Hospital for Special Surgery: Tips for Avoiding Muscle Fatigue When Exercising
- Columbia University: Go Ask Alice! - Is It Okay to Feel Lightheaded and Dizzy After Physical Activity?
- MedlinePlus: Rhabdomyolysis