Hi,
1.having sex can cost you calorie, means you need energy for having sex and maintain normal stance after sex, you need energy.
There are many ways you can maintain energy or stamina:
1. Doing regular exercise
2. Doing yoga
3. Having properly balanced food
4. Proper sleep pattern
5. If you have any habit of
smoking or alcohol need to reduce or stop these are basic things.
If it's related to the medical issue.
1. Check your Blood sugar
2. Check your blood pressure
3. blood iron level, Vit D3 level, B12 level
4. Check for any
hormonal imbalance.
5. Chest X-ray and ECG to find any issue with your Lung or Heart.
6. Obesity
Or in general, you can go for a master health check-up in a good institution and work your way.
Hope I have answered your query. Let me know if I can assist you further.
Take care
Regards,
Dr S.R.Raveendran, Sexologist