Medical Compass: Hydration during the ‘heat’s on’ months

Mild dehydration can lead to decreased concentration, subdued  mood, fatigue and headaches

By David Dunaief, M.D.

Dehydration typically gets attention during the summer months, when we spend more time outside in the heat. However, during the cooler winter months, it can also be troublesome. Dry heat quickly evaporates moisture in the air, making it hard to stay hydrated.

Complications and symptoms of dehydration can be mild to severe, ranging from constipation, mood changes, headaches and heart palpitations to heat stroke, migraines and heart attacks.

In addition, the dry air can make our throats and sinuses dry, making us uncomfortable and more susceptible to irritations and viruses.

Dehydration is simple to avoid, right? Not necessarily. We may be dehydrated before we’re thirsty. Let’s look at some of the consequences of dehydration and suggestions for avoiding it.

Tension-type migraines

In a review of studies published in the Handbook of Clinical Neurology, those who drank four cups more water had significantly fewer hours of migraine pain than those who drank less (1). Headache intensity decreased as well.

Heart palpitations

Heart palpitations are very common and are broadly felt as a racing heart rate, skipped beat, pounding sensation or fluttering. Dehydration and exercise are contributing factors (2). They occur mainly when we don’t hydrate prior to exercise. All we need to do is drink one glass of water prior to exercise and then drink during exercise to avoid palpitations. Though these symptoms are not usually life-threatening, they are anxiety producing for patients.

Heart attacks

The Adventist Health Study, an observational study, showed a dose-response curve for men (3). In other words, group one, which drank more than five glasses of water daily, had the least risk of death from heart disease than group two, which drank more than three glasses of water daily. Those in group three, which drank fewer than two glasses per day, saw the least amount of benefit, comparatively. For women, there was no difference between groups one and two; both fared better than group three.

The reason for this effect, according to the authors, may relate to blood or plasma viscosity (thickness) and fibrinogen, a substance that helps clots form.

Decreased concentration

In a study, mild dehydration resulted in decreased concentration, subdued mood, fatigue and headaches in women (4). In this small study the mean age of participants was 23, and they were neither athletes nor highly sedentary. Dehydration was caused by walking on a treadmill with or without taking a diuretic (water pill) prior to the exercise. The authors concluded that adequate hydration was needed, especially during and after exercise.

I would also suggest, from my practice experience, hydration prior to exercise.

Staying hydrated

Now we realize we need to stay hydrated, but how do we go about this? How much water we need to drink depends on circumstances, such as diet, activity levels, environment and other factors. It is not true necessarily that we all should be drinking eight glasses of water a day. 

In a review article, the authors analyzed the data, but did not find adequate studies to suggest that eight glasses is supported in the literature (5). It may actually be too much for some patients.

You may also get a significant amount of water from the foods in your diet. Nutrient-dense diets, like Mediterranean or Dietary Approaches to Stop Hypertension (DASH), have a plant-rich focus. A study notes that diets with a focus on fruits and vegetables increases water consumption (6). As you may know, 95 percent of the weights of many fruits and vegetables are attributed to water. An added benefit is an increased satiety level without eating calorically dense foods.

Remember that salty foods can be dehydrating, including breads and pastries, so try to avoid these.

Are caffeinated drinks dehydrating?

In a review, it was suggested that caffeinated coffee and tea don’t increase the risk of dehydration, even though caffeine is a mild diuretic (7). With moderate amounts of caffeinated beverages, the liquid has a more hydrating effect than its diuretic effect.

Keeping some humidity in the air

To reduce sinus inflammation and dry skin that you can experience with heated air, measure the humidity level in your home with a hygrometer and target keeping it between 30 and 50 percent (8). When the temperature outside drops below 10 degrees F, lower this to 25 percent.

Strategies for adding moisture to the air include using cool mist humidifiers, keeping the bathroom door open after you bathe or shower, and placing bowls of water strategically around your home, including on your stovetop when you cook. If you use a humidifier, take care to follow the manufacturer’s care instructions and clean it regularly.

It is important to stay hydrated to avoid complications — some are serious, but all are uncomfortable. Diet is a great way to ensure that you get the triple effect of high nutrients, increased hydration and sense of feeling satiated without calorie-dense foods. However, don’t go overboard with water consumption, especially if you have congestive heart failure or open-angle glaucoma (9).

References:

(1) Handb Clin Neurol. 2010;97:161-72. (2) my.clevelandclinic.org. (3) Am J Epidemiol 2002 May 1; 155:827-33. (4) J. Nutr. February 2012 142: 382-388. (5) AJP – Regu Physiol. 2002;283:R993-R1004. (6) Am J Lifestyle Med. 2011;5(4):316-319. (7) Exerc Sport Sci Rev. 2007;35(3):135-140. (8) epa.gov (9) Br J Ophthalmol. 2005:89:1298–1301.

Dr. David Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com.