Friday, July 07, 2006

Hot as Hell: When It's 95 Degrees and Humid, Do You Really Want to Be a Hero?

Hot, hazy, and humid.

That was the forecast. It was going to be hot as hell. Sure enough, when the day arrived, it was to the hum of air-conditioners and the whir of oscillator fans and reports of "code red" heat emergencies.

It was going to be in the 90's and the heat index was expected to be 105. People would be doing everything they could to keep cool, from moving as little as humanly possible to staying submerged in water.

Me? I was out on the tennis court playing a match against my friend and opponent, Jim. The photo shows me sucking air after our "warm-up." I had asked Jim if we could start our match at 8:30 in the morning instead of 9:00. I figured a half hour earlier would gain us a few degrees less in temperature and a little more air -- and perhaps save us from collapsing from heat exhaustion.

Some like it hot. In summer, when people flee in droves from humid enclaves of South Florida and desert communities in Southern California, Nevada, and Arizona, these heat fiends arrive looking forward to toasty temperatures of up to 110 degrees.

They even play tennis in the heat and the hotter the better. One fellow I knew would only play matches at high noon in the heat of the day. He had a high tolerance for extreme heat. Comfortable in the searing heat, he lobbed and dropshot opponents with much different thermostats until they invariably wilted.

I refused to play him at high noon. I told him it was a time fit only for mad dogs and Englishmen. He finally agreed to play me at a more civilized hour, in the long-shadowed cool of late afternoon. I won in straight sets and he never wanted to play me again.

He probably would have killed me in the heat. You see, I'm a polar bear. In winter, I roll around in the snow. I could curl up and go to sleep on an ice floe. All my life, I have been an ice hockey player. I am literally never cold.

But put me out on the tennis court on a scorcher like this one, and I'm a polar bear plopped into the Nevada desert. Not that I can't perform in the heat. I can. But, to be honest, I don't have the same level of energy and endurance and I don't enjoy playing as much.

Also, since I have been writing this blog about health and longevity, I have learned a little something about the human body's mechanisms for coping with heat. And I know that heavy exercising in extreme heat can lead to heat exhaustion and heat stroke.

I love tennis but I don't love it enough to die playing it.

So this was my upbeat attitude as Jim and I began our warm-up. Both of us like a nice long warm-up, a misnomer on this furnace of a day because I was warmed up when I took the court. After a few minutes of hitting, the sweat was pouring out of me.

After fifteen minutes, we sat on the bench mopping up sweat and pouring water and Gatorade into us, I the water and Jim the sports drink. And this was before we began playing. I prefer water but I also know that on a day like this Jim's choice may be giving him an extra edge.

Playing hard on such a day (the only way I know and the only way Jim knows), a tennis player can easily lose two quarts of water an hour and must be careful not to get dehydrated. In drinking water, I replace lost water which is good. But in drinking Gatorade, Jim also replaces lost electrolytes essential for muscle movement and gets additional glucose to fuel aerobic respiration.

Bear with me for a bit while I explain electrolytes. Electrolyte is a "medical/scientific" term for salts, specifically ions. The term electrolyte means that the ion is electrically-charged and moves to either a negative (cathode) or positive (anode) electrode.

Our body fluids -- blood, plasma, interstitial fluid (fluid between cells) -- are like seawater and have a high concentration of sodium chloride (table salt, or NaCl). The electrolytes in sodium chloride are: sodium ion (Na+) - cation and chloride ion (Cl-) - anion. In the human body, the major electrolytes are : sodium, potassium, chloride, calcium, magnesium, bicarbonate, phosphate, and sulfate.

Electrolytes are important because they are what our cells (especially nerve, heart, muscle) use to maintain voltages across their cell membranes and to carry electrical impulses (nerve impulses, muscle contractions) across themselves and to other cells. Our kidneys work to keep the electrolyte concentrations in blood constant despite bodily changes.

When we exercise heavily, we lose electrolytes in our sweat, particularly sodium and potassium. These electrolytes must be replaced to keep the electrolyte concentrations of our body fluids constant.

So, many sports drinks, such as Jim's Gatorade, have sodium chloride or potassium chloride added to them. They also have sugar and flavorings to provide the body with extra energy and to make the drink taste better.

However, in defense of water, let me say that sports drinks can be too much of a good thing. They are in every sports locker room as a sort of E-Z Pass of electrolyte replenishment. Some kick things up a notch by adding an "energy" formula containing more stimulants than a cup of coffee.

But an energy drink laced with stimulants from various sources (guarana, ephedra, etc.) can cause problems, according to David Ellis, a sports nutrition expert and registered dietician.

"They blunt your perception of pain," Mr. Ellis said. "That might be good in the short term, but the bad news is if you don't feel the fatigue in a hot, humid environment, your body won't make you slow down to minimize overheating. Exertional heatstroke is a real possibility."

Exertional heat illness occurs when the heat generated by exercise, and made worse by hot weather, cannot be dispersed quickly enough by the body, primarily through sweating. It's basically a heat "build-up," called hyperthermia, that can be lethal in its most extreme form, heatstroke.

We humans have limited ways of maintaining a normal body temperature. Anyone can go hyperthermic in the right conditions. And when you are 68 as I am, and out on a tennis court in boiling heat and humidity, and playing someone as tough as Jim, these are certainly some of the right conditions.

Tennis is no walk in the park, either. It is a game of movement, of bursts of speed, of sudden accelerations and change of direction. It makes extraordinary demands on muscles, heart, and lungs. Fortunately, this remarkable body of ours orchestrates it all, efficiently summoning all the required resources to keep Jim and me moving, and does so completely on its own.

I didn't have to tell my body that I was heating up and it was time for the sweat to flow to help me get rid of excess heat. My brain's thermostat (hypothalamus) had already picked up the rising body temperature and was issuing urgent orders (nerve impulses) to sweat glands under the skin. When such orders go out, all hands, from major organs to foot soldiers at the cellular level, salute and swing into action. Their goal: cool me down.

Already I am a little flushed with extra blood flow to the skin, which is an important part of the cooling process. As elevated blood flow disperses to large areas of the skin, heat is released. A flushed face is a sign that this heat-release process is taking place.

Both of us are already soaked with sweat, the main way the body gets rid of heat and cools itself. The fluid for the sweat comes from the increased blood flow. The sweat evaporates from the skin, removing heat and cooling the body (but also removing fluid that must be replaced).

However, in a hot, humid environment such as today, sweat has difficulty evaporating and may not be able to do so at all. In this case, the cooling system can be seriously compromised or break down altogether. In the latter case, we're talking a life-threatening condition: heat stroke.

Symptoms of heat stroke are: core body temperature rises abobve 104 degrees; sweating ceases; heart rate accelerates; there is a struggle to take deep breaths; confusion, dizziness, nausea, and headache. A victim can collapse, lose consciousness, and die.

Two points: 1) Heat stroke is nothing to mess with and 2) Playing a hard game of singles tennis on a sweltering day is not exactly bright.

We begin the first set with me serving. As aways when Jim and I play, the points are long and hard. I attack and Jim gets everything back. To win a point against Jim, you have to hit an almost perfect shot hard and deep to the corner. Anything short, he puts away.

Back and forth the ball goes over the net in long points. Jim's game is to outlast me in long rallies; my game is to attack and win the point quickly. The score gets to deuce or even. Then we take turns getting the advantage only to have the score fall back to deuce.

Neither one of us holds back. We run flat out after wide balls. I charge the net hoping to make a winning volley. Jim runs down my best shots, keeping the ball in play, making me work for everything. It is raw muscle power in action.

For both of us, an incredibly complex set of bodily processes swing into action to keep our muscles driving this continuous movement. Our bodies automatically orchestrate responses involving the heart, blood vessels, nervous system, lungs, liver, and skin.

Our hearts, those amazing muscles, beat faster and faster, pumping out more and more oxygen-rich blood to feed the working muscles of a couple of tennis machines. By now our hearts have increased blood flow by about four or five times from the resting state.

We begin to breathe faster and deeper. The lungs and the entire respiratory system produce more and more oxygen for the blood. Blood that normally goes to major organs such as the kidney, intestines, and stomach is diverted to the muscles. This diversion keeps our muscles powering us all over the court.

The sweat is flowing and dripping down on my glasses. I have to pause from serving to wipe big droplets from my glasses. I'm aware of my heart. I know what I am putting it through. The first game, which has gone on and on, is finally over and I win it. It is 1-0.

We're both glad to get to the bench where we sit while Jim chuggalugs Gatorade and I do the same with water. We talk about how hot it is and I mention that I'm going to do a piece for this blog on playing tennis in extreme heat.

He says he looks forward to reading it. I take out my camera and we take pictures of each other. I ask Jim how old he is and he refuses to tell me. "If I tell people how old I am, they'll think they should beat me. I don't want them thinking that." I told him that I was going to research public records, find out his age, and tell everybody.

What was going on was that I was losing my appetite for going back out there in this heat. We were both soaking wet. I was thinking: We had played just one game and it had been like World War I. What would a set be like? What would two sets be like in this heat?

Did I hear somebody out there say, "death wish"?

Tennis is supposed to be fun and I do love it. Ordinarily, I revel in it: the dashing around the court; the sheer exhilaration of movement; the magic of eye/hand/legs coordination in play at every shot; the thrill of watching the ball, striking the sweet spot, following through, and hitting a winner; the challenge of coming back from behind; the joyful irresponsibility of just being out there. Such a wonderfully silly thing for a grown man with seven grandchildren to be doing.

Yet on this blistering day, I went back out on the court slowly. My mind was no longer on tennis but on the heat and it showed in my play. Instead of attacking, I hung back waiting for Jim to make an error. As usual, he did not oblige. Instead, I made errors. I missed shots that I rarely missed.

Jim reeled off four straight games. With the score 1-4 in Jim's favor, I went to

the net and said, "Jim, it's too hot for tennis. Do you mind if we quit?"

Good guy that he is, he didn't mind. I think he was feeling the heat, too (picture of him above).

Am I a quitter? Yes, and I'd do it again. Although after about 45 minutes I was not in distress, not even close to it, in another hour I might well have been. When you're 68 and not yet acclimated to the heat -- it was my first match of the summer in such heat -- extreme heat is not your friend. Non-acclimation is yet another risk factor for heat exhaustion or worse.

I could have toughed it out, but why? It was not as if we were playing on national TV and I owed millions of viewers an over-the-top performance. It was not as if my kids and grandkids were counting on me to hold up the family honor.

It was just Jim and me. Does he think less of me? I don't think so. Do I think less of myself? No.

Bottom line: extreme exercise in extreme heat is dangerous. I see no sense to suffering in the heat and taking unnecessary health risks for -- a game.

And, besides, I'm a polar bear.

So long and keep moving.