Deep diving increases the amount of nitrogen dissolved into the body.
Nitrogen dissolved in the body bubbles causes decompression sickness by inappropriate behavior before and after diving.
Use a dive computer or dive table and follow the below rules to make a comfortable diving.

If you do not follow the rules・・・・

Elderly and obese people should keep diving time as short as possible.

Have fun without overdoing

Sleep well the day before and stop diving if you are overly tired or unwell.

Use a suitable suit to keep body temperature.

Be carefully about cold in deep diving！！

Do not alcohol and smoking just before and after diving.