When you feel tired, sluggish and heavy after climbing outdoors, your energy levels have dropped and as sweat evaporates from your skin it takes heat away from your body, but you also lose body fluids. Your concentration and focus begin to wane.
Therefore, you need to drink water during exercise to replace the water lost during sweating.
Water is the source of life and every cell in your body needs it to stay hydrated. The recommended amount of water for a healthy adult is 1500-1700ml per day. Not drinking water or drinking too little, as well as drinking quickly and vigorously after exercise, also tends to increase the burden on the heart and tends to cause thickening of the blood, triggering heart attacks and even death from overdrinking.
Therefore, using water bottles with straws allows you to get into the habit of drinking small amounts of water several times during outdoor exercise, maintain a normal water intake and develop the habit of drinking in moderation.