" Dehydration — no matter which season we’re in — is always dangerous. After all, up to 60% of a person’s body weight is water, and it only takes a 1- to 2% drop in that percentage to cause dehydration. 3 Tips to Staying Hydrated This Winter Carry a water bottle with you. You know that it is important to drink water before, during and after you exhort energy, but drinking water during the day is ...