These are my experiences.
Before workout at gym, follow the following rules.
- Eat food and drink water 3 hours prior to workout. Otherwise, you will vomit.
- During workout, drink just few water. Otherwise, you will vomit.
- Relax intervally each exercise. Otherwise, you will feel fatigue.
- Breath with nose at normal respiratory rate, not with mouth at rapid respiratory rate when tired. Otherwise, the lungs may not catch oxygen consumption fully and the body will release much energy.
- Understand what is core muscle for each exercise. Otherwise, supportive muscle will benefit rather than core muscle.