Andrew Siegel, M.D. Blog #113
As I sit here writing, it is 100 degrees Fahrenheit in the New York metropolitan area. We are in the thick of an absolute hellish heat wave, as we have been for the past several weeks. I prefer the heat to winter frigidity, but current weather conditions make it very unpleasant to be outside and, more importantly, these temperatures can be downright dangerous to one’s health, causing an entire host of very unpleasant symptoms that if not attended to can result in heat stroke and even death.
I became dehydrated last weekend, a miserable incident that has happened a few times in my lifetime. It happened after cycling with my sister, her friend and a few of my friends. It was 95 degrees Fahrenheit and near 100% humidity. I picked up Michael in my wife’s hybrid SUV and with our two bikes on the rack headed to Fort Lee, parking near the George Washington Bridge. I consumed a bottle of water in the car while driving, because I knew it was going to be a scorcher, and had two full bottles on my bike of iced water and iced coconut water. Our group rode 45 or so very hilly miles that day. We did the Palisades Interstate Park starting at Fort Lee and then headed up north and exited the park to enter 9W. We cycled past the Tappan Zee Bridge and ended up at Nyack Beach State Park. We put in nearly 3 hours of cycling time, with a bunch of rest stops, totaling about 5 hours of outdoor exposure time. I really thought I could keep up with my water losses, but I was clearly in the wrong.
We initially stopped for a breather near the police station in Alpine after a tough climb and the entire group was already drenched. Our next break was at the Community Market in Piermont for a water refill and a short recess. We turned around at Nyack Beach State Park and two of our group departed for home, but four of us stopped at the Runcible Spoon for a smoothie, a carbohydrate recharge, another water replenishment, and a nice break. Thereafter, our foursome maintained a well-executed pacing line for the remainder of the return trip, which was predominantly on Piermont Road, with a final rest stop before descending the hills of Tenafly. At this stop, all of us felt “not quite right.” My sister experienced chills and nausea; I felt incredibly hot and my pulse was racing away and our two friends were entirely relieved to be out of the saddle and the sun for a few minutes. During the final ascent, both of my quads experienced simultaneous cramps, but our group ultimately made it back intact. I ripped off my sweat-weighted cycling jersey and turned the AC in the SUV to max. As I drove home I felt light-headed and experienced a strange visual occurrence in which everything that was white in color appeared glaringly and strangely bright to me—kind of the way heaven is portrayed in movies!
When I arrived home, I felt out of sorts; I was exhausted and my heart was still racing and all I wanted to do was to lie down—I truly felt as if a truck had hit me! I couldn’t seem to find the keys to the SUV to return to my wife, hunted in vain for them, but ultimately discovered them tucked into the front waist of my cycling shorts—clearly I was not playing with a full deck!
I had a mid-afternoon lunch, drank almost two more bottles of water and mustered up the energy to shower. I headed to the couch, where I proceeded to read the Sunday paper. I developed an awful headache and took a few Motrin with some more water. My family was supposed to go out for dinner that evening, but I felt so sluggish that I just wasn’t up for it. After having take-in Chinese food for dinner (certain to rebalance my sodium deficit!) I spent the evening on the couch, watching “The Borgias” and “Prison Break.” By 9PM I realized that I hadn’t urinated in 12 hours. When I did, the urine was dark and concentrated. Ultimately, after a pretty decent night’s sleep, I was back to normal in every respect. However, in retrospect, I recognized that I had suffered with dehydration, a very dangerous problem that has the potential to kill human beings.
Dehydration is a state in which there is excessive loss of body water and therefore a disturbance in our metabolic processes and functions. As a result of excessive fluid loss, there is decreased blood volume (hypovolemia) and consequently, lower blood pressure and a faster heart rate with less delivery of oxygen and other nutrients to our tissues, and less removal of waste products. Under these circumstances, it is common to experience “orthostatic” changes—feeling light-headed and dizzy when arising from a supine or sitting position. Often one experiences a dry mouth and profound and sometimes insatiable thirst. It is typical to feel nauseated, sleepy, lethargic, fatigued and generally awful, not dissimilar to the sensation of being hung over. Mental confusion and even delirium are real possibilities. One’s urine becomes very dark and concentrated as the kidneys make every effort to reabsorb water back into the body. Urine production therefore becomes minimal. Skin can lose its healthy consistency, becoming dry, shriveled and much less elastic. Sweating and tearing can cease and body weight can drop significantly. 60% of our body weight is water, of which two-thirds is within cells and one-third in our blood and interstitial fluid (fluid between our cells). For a 70 kg man, that amounts to 42 kg of water. It doesn’t take too much in the way of fluid losses to throw one over the brink into dehydration. The long and the short of it is that dehydration can and will negatively affect every cell, tissue and organ in the body.
Dehydration can severely impact one’s athletic performance. Endurance athletes such as marathon runners and cyclists are particularly susceptible because of the amount of time they spend exercising and the extent of sweating that comes with the territory. Dehydration is cumulative, such that a fluid deficit from a previous day’s effort carries over to the next day. Exercising in high altitude areas increases the degree of the risk. The greater the temperature, the greater the risk, and the same goes for humidity, since sweat cannot evaporate as efficiently under severely humid conditions as it can under dry ambient conditions.
Tips To Avoid Dehydration
• Don’t be a fool like me and spend hours doing a strenuous endurance event when it is ridiculously hot and humid out. In the circumstances of really high temperature and humidity, go to the gym or for a swim to get your exercise dose.
• Hydrate, hydrate, hydrate…the best endpoint is urine approaching the color of water; if it looks like apple cider it is a sign of dehydration. Drink abundantly before, during, and after exertional activities.
• Wear light gear that wicks the sweat from your body and that promotes evaporation.
• Avoid strenuous exercise at the peak heat of the day—early morning or late afternoon are preferred times.
• The young and the elderly are at higher risk, so this population should hydrate to an even greater extent.
• Be particularly careful about dehydration if you take a diuretic or drink a lot of caffeine or alcohol, since you will be particularly prone from the dehydrating effect of these substances.
Bottom Line: Always be cognizant of weather conditions when undertaking any type of outdoor activity. Remember, Mother Nature rules supreme and is not something to take lightly…serious, or even deadly, consequences can be the result.
Andrew Siegel, M.D.
Author of Promiscuous Eating: Understanding and Ending Our Self-Destructive Relationship with Food: http://www.promiscuouseating.com
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