Hot summer days are synonymous with enjoyable outdoor pursuits, such as family days out, visits to the beach and dining al fresco. But hot weather can cause unpleasant symptoms, such as extreme fatigue, in susceptible people. Finding shade, resting and having cool drinks may quickly relieve discomfort and listlessness during hot days. If you are elderly, or in weakened health, and you are unaccustomed to hot weather, it's important to stay in tune with your body and to heed early warning signs of extreme fatigue.
Environmental temperature fluctuations, especially sudden and extreme changes such as a heat wave, can cause tiredness while the body adapts to the change. If you are used to a mild, temperate climate where temperature fluctuations are relatively small, you may feel tired if you travel and need to adjust to a hotter climate. As the body adapts to higher temperatures, symptoms of fatigue will ease.
Dehydration is a common cause of tiredness during hot weather. Dehydration occurs when body weight decreases by 1 percent or more because of fluid loss, according to the United Kingdom's National Health Service. Other symptoms of dehydration include headaches and the production of strong-smelling, dark yellow urine. To prevent tiredness caused by dehydration during hot weather, drinking fluids regularly throughout the day. In general, clear urine is a sign of a well-hydrated body.
Hot weather may cause you to experience restless nights, which can result in extreme fatigue during the following day. According to Dr. Chris Idzikowski, author of "Learn to Sleep Well," mild environmental temperatures are conducive to restful sleep, but temperatures above 75 degrees may cause insomnia.
Hyperthermia or heat-related illness is particularly hazardous for elderly people and for people who have medical conditions such as high blood pressure. Extreme fatigue accompanied by nausea, dizziness and cool, clammy skin signals a condition called heat exhaustion. The afflicted person requires immediate treatment to lower his body temperature. Extreme fatigue accompanied by dry, flushed skin, a severe headache, confusion and a rapid pulse may indicate heat stroke, a potentially life-threatening condition that requires urgent medical attention.