Sweating is the body's way of decreasing its internal temperature. Heavy sweating means the body feels the need to provide ample cooling, but it also means the person is losing a lot of liquid. A person who is sweating heavily could soon get dehydrated and overheat. As a person heats up, the heat can affect their thinking. They may feel lightheaded or look off-balance. Ask if they need to sit down, and help them get somewhere shaded or cool. The person may also have a headache, a related symptom. People with heat exhaustion may throw up or complain of feeling sick to their stomach. If the person is vomiting and showing other signs of severe heat exhaustion, such as dizziness or severe fatigue, get medical help as soon as possible. People with heat exhaustion may complain of feeling extremely thirsty or dehydrated. Get them to a cooler place and encourage them to sip some water. The person may be starting to get dehydrated, which can lead to muscle cramps. They may also be extra tired or fatigued, or look like they can't quite stand up. and increased breathing rate. Heat conditions can increase a person's heart rate significantly. A heart rate over 100 beats per minute is considered high, but anything above the person's normal heart rate is cause for concern. You may also notice the person breathing rapidly.  Ask the person if they feel like their heart is racing. Also, see if they know what their normal heart rate is. To take their pulse, find the vein on the inside of the wrist between the tendon and the wrist bone. Use your index and middle fingers to feel for the pulse. Count heartbeats for 30 seconds, using a watch or timer to check the time. Multiply the heartbeats by 2 to get beats per minute. When a person's body starts getting overheated, the blood vessels constrict near the skin due to dehydration and low blood pressure. This condition results in pale skin. Their skin may even feel cool to the touch. . Use a thermometer to take the person's temperature in their mouth, ear, or armpit. With heat exhaustion, their temperature may be at 100 to 102 °F (38 to 39 °C) as their body gets too warm.  To take an armpit reading, place the tip of the thermometer in the person's armpit and hold the arm down. For a mouth reading, insert the tip of the thermometer under the tongue near the back of the mouth. For an ear reading, insert an ear-specific thermometer in the ear canal.  Follow the directions for the thermometer. Digital thermometers often read the person's temperature instantly or within 30 seconds, while a glass thermometer can take up to 5 minutes for a good reading.

Summary:
Pay attention to heavy sweating. Look for dizziness and balance issues. Make note of nausea or vomiting. Find out if the person has increased thirst. Notice muscle cramps and tiredness. Check for a high pulse Check for pale, clammy skin. Take the person's temperature