Heat??

[Blueberry]

I pay attention because I'm sensitive to it. I also feel like we're having more bad air days this year than in the recent past (could be selective memory, but I don't think so). At least we haven't had a code purple in a long time.

[Crankin]

I pay a lot of attention it this. I don't do well in the heat, especially the heat and humidity. And when that happens, we get bad air quality. I have asthma that is totally not an issue for me, but I don't want it to become one. I barely survived a 15 mile ride Tuesday in the heat of the day. It was very humid, the sun was blazing, although it was only 80. Last year I forced myself to ride in hot weather, but mostly started early in the AM. It was just too hot on too many days to do stuff inside.
We just finished 3 hours of rain/thunder and I am getting ready to ride to an appt. I am only doing this on the hottest/most humid day of the year because it's cloudy and the rain cancelled my early AM ride with Hirakukibou.

[PamNY]

I tolerate heat fairly well, but acclimation is important for me. This current heat wave is just too early for my body to be ready!

[Jo-n-NY]

I ride better in heat than cold. I love warmth, however I plan my rides accordingly either early morning or early evening. It was in the 90's yesterday but I met dh after work and we did a nice 15 mi loop at 6:30 which was perfect!

~ JoAnn

[Grits]

Another rider here from NC. We typically start our rides at 7:30 or 8:00 in the morning - have gone as early as 7:00 when we were doing an extra long ride. We try to be finished by or before noon. We do shorter rides late in the afternoon. I hope that we get some relief from this extreme heat and have some more normal temps for the season. 80's would be more typical. Riding in 90+ temps and pushing it would be hard on many riders - including me!

[jlnc]

Good to know I am not the only one affected by it Grits! Thanks.

[nscrbug]

I've noticed that I haven't acclimated too well to the heat this year. Mind you, we've only had a handful of really warm days, so far....but, normally I can tolerate warm temps better than the cold. The cold seems to worsen my asthma, while the heat and humidity don't affect it at all. I just don't care for the inconsistency of the temps in my area lately...one day it's 96 (like yesterday) and the next day it's in the 60's (today)...ack! If the temps would stay in a certain range for a while, it would be easier to acclimate...rather than this constant up/down crap.

[emily_in_nc]

This is about as bad as it normally gets in NC - but it's already been this way for ~2-3 weeks, and there's not much of an end in sight. I think we're in for a LONG, HOT summer, sadly.

Just like last year...I remember it well because we were in the process of moving in June, and there were several 100+ days, followed by something like ninety 90+ days. Our main moving days were over a weekend with highs of 96-98 with high humidity. Many treks up to the third floor with sweat dripping from every pore.

When we finally got unpacked and settled in and started riding...OMG. The heat, sunshine, humidity was brutal for months. Seem to recall that at least a couple of the months (maybe more than a couple) where the "hottest ever" for that month.

NC...gotta love it.

[sundial]

Heat combined with high humidity is brutal and despite any efforts to remain hydrated, it can still take you down. It does help to gradually increase your effort in hot weather to improve your tolerance for heat, but there may come a point in which you simply cannot tolerate heat.

[Catrin]

I do think it is wise to choose one's route based on the level of heat/humidity. While my short rides are 20-23 miles regardless of how hot it is, it makes a massive difference if it is within the hilly but quite shaded nature park across from my apartment complex, or the flat country roads though the corn fields with no shade at all.

I have asthma, and I've yet to have any problems with heat and humidity while riding as far as the asthma is concerned. I seem to be far more sensitive to colder weather in this department. My allergies even seem to have disappeared since I started riding!

I also have given myself permission to not ride if the temps exceed 95 or if the heat index breaks 100F. Depending on conditions I can still ride in the park in those temps, but if it is just too oppressive then I won't. We don't NORMALLY have too many days where temps get higher than that - if I lived elsewhere that would likely have to chance if I wanted to ride regularly. The important thing is to acclimate your body to where you live

[zoom-zoom]

On Tues. hubby and I had planned a 70+ miler in preparation for our first century ride next weekend. It was the only day that worked for us both, partly because DS was on a camping trip with his class overnight, so DH was still able to get a half-day of work in.

So we start our ride and it's in the 90s. We headed inland a bit and it was easily pushing 95...and humid. In farmland with no shade. By 12 miles in I had already chugged a 24oz bottle, but was feeling chills and weak...not good. We slowly made our way back towards the lakeshore and decided to bag the ride, completing half of our planned distance (originally the plan was to ride 45+ just the two of us, then join our LBS for their 28 mile Tues. night ride).

Even before we decided to cut short we'd decided to cut back to 60 or so. But by 25 miles in we both agreed that it was foolish to even do that.

I am still feeling a bit off after that. We had no chance to acclimate. We had an endless Winter with only a few weeks of "Spring" weather. 5 weeks ago we had snow, so that sudden jump from 50s and 60s to 90s was more than my body could tolerate. Last year we did a 75 miler in early July under similar conditions and I was OK, but I'd had a month of acclimatization to warmer temps by that point. I'm also recovering from a cold and battling allergy and asthma issues, so the air quality definitely played a role.

[grey]

On the first 90+ degree day, the guys I ride with wanted to have a 25+ mile hill day, starting at 5:30pm. This was a VERY BIG mistake - I hadn't been riding regularly enough, and certainly hadn't acclimated to the heat yeat. The next day, I was tired and had heart palps.

Heat always knocks several miles off me for the first few weeks. I add Nunn tablets to my water - sometimes in both bottles. I also organize rides for 7-7:30am. You do adjust, sometimes it takes a while. Glad you didn't try to push through. Dizzy/chills is a big warning sign to stop, rest in the shade and drink, drink, drink.

I also carry a bandanna with me - when it gets hot, I soak that bugger and put it on my head under my helmet. It helps.

[tulip]

Ride early in the day if you can. Commuting to work is an ideal way to ride early. Of course, you still have to ride back after work, and it might just be too hot. Take it slow, and if its too hot, don't ride.

[zoom-zoom]

Heat always knocks several miles off me for the first few weeks. I add Nunn tablets to my water - sometimes in both bottles.

Yep. I had a bottle of Powerade, a bottle with a Nuun tablet, 5 Endurolytes capsules, and ~80oz of fluids during that miserable ride. I ended covered in salt residue and soaked. I think the humidity was just as responsible for my symptoms as the heat. My sweat wasn't evaporating well at all.

[emily_in_nc]

Dr. Gabe Mirkin's e-zine this week contained a very interesting article about the need for salt during hot-weather rides. I am going to start taking more salty snacks along this time of year as I am sure I am not getting enough on the long, really hot rides where I come home dripping wet.

This week's issue is not yet posted on his site (that I could see) - should be soon. I'm copying it below:
http://www.drmirkin.com

Dr. Gabe Mirkin's Fitness and Health E-Zine
June 12, 2011

Why You Need Salt During Prolonged Exercise in Hot Weather

The only mineral that you need to make extra effort
to take during prolonged exercise is sodium. The amount of
salt people need varies greatly from person to person. If you
exercise regularly for more than an hour, particularly in hot
weather, you probably need extra salt.
YOU DO NOT NEED EXTRA POTASSIUM, MAGNESIUM OR
CALCIUM: Healthy athletes and exercisers do not need to take
potassium, magnesium, calcium or any other minerals (1).
Athletes do lose minerals through increased sweating, but
compared to blood, sweat is very dilute in minerals, so they
can get all the minerals they need from food. A deficiency of
potassium, magnesium, or calcium has not been reported in
healthy athletes who eat a normal diet.
SODIUM: The definitive studies on minerals and
exercise were done during World War II. Dr. James Gamble of
Harvard Medical School paid Harvard medical students to lie on
a raft or exercise in his swimming pool, take various amounts
of fluids and salt, and have blood drawn to measure salt and
mineral levels. He showed that salt requirements increase
significantly when you exercise for several hours in hot
weather. I was fortunate enough to be among the doctors
training at Harvard Medical School who heard Dr. Gamble give
his lectures on minerals and exercise. Now, more than sixty
years later, nobody has improved on his research.
YOU NEED EXTRA SALT IN YOUR FOOD WHEN YOU EXERCISE IN
HOT WEATHER: If you don't take salt and fluids during
extended exercise in hot weather, you will tire earlier and
increase your risk for heat stroke, dehydration and cramps.
Not taking in salt when you exercise for more than two
hours can prevent you from retaining the water that you drink.
It can also block thirst, so you may not know that you are
dehydrated. Thirst is a late sign of dehydration. You lose
water during exercise primarily through sweating, and sweat
contains a far lower concentration of salt than blood. So
during exercise, you lose far more water than salt, causing
the concentration of salt in the blood to rise. You will not
feel thirsty until the concentration of salt in the blood
rises high enough to trip off thirst osmoreceptors in your
brain, and it takes a loss of two to four pints of fluid to do
that (2).
YOU NEED SALT TO RETAIN THE FLUID YOU DRINK WHILE
EXERCISING. In one study, female competitive distance runners
took in drinks with different concentrations of salt during a
four-hour run (3). Ninety-two percent of those who took in
plain water with no additional salt developed low blood levels
of salt.
Taking in fluid without also taking in adequate
amounts of salt dilutes the bloodstream, so that the
concentration of salt in the blood is lower than that in brain
cells. This causes fluid to move from the low-salt blood into
the high-salt brain, causing the brain to swell, which can
cause seizures and death. However, hyponatremia, the low salt
syndrome that can kill athletes, is usually caused by taking
in far too much fluid, rather than from not taking in enough
salt.
HOW SALT CAN IMPROVE PERFORMANCE IN COMPETITION:
Taking extra salt just prior to competition can help you
exercise longer and harder (4). Fatigue during hot-weather
exercise is caused by lack of water, salt, sugar or calories.
Of the four, exercisers are most ignorant of their sodium
needs.
SALT AFTER EXERCISING IN THE HEAT: You should always
replace fluids, salt, sugar, and protein after you exercise in
hot weather. (5). Just salting your food to taste should
replace the salt you lose through heavy sweating (6). If your
kidneys are normal, you should be able to rid yourself of any
excess salt that you may take in.
CAN YOU HARM YOUR HEALTH BY CAUSING SALT DEFICIENCY?
If you are not replacing salt that you lose from sweat, you
will suffer fatigue, muscle cramps and injuries that can
prevent you from continuing to exercise. Severe salt
deficiency can cause high blood pressure and metabolic
syndrome. While moderate salt restriction can lower high blood
pressure, severe salt restriction can raise blood pressure.
When you don't get enough salt, your adrenal glands put out
large amounts of aldosterone that constricts arteries and
raises blood pressure, and your kidneys put out extra renin
that also constricts arteries and raises blood pressure (7).
SEVERE SALT RESTRICTION CAN RAISE BLOOD SUGAR AND
INSULIN LEVELS: A study from Columbia University Medical
School showed that salt restriction raises blood sugar and
insulin levels, while adding salt lowers them (8).
SALT YOUR FOOD, NOT YOUR DRINK: Salty drinks taste
awful, so it is easier to meet your needs with salted foods.
If you plan to exercise for more than a couple hours in hot
weather, drink one or two cups of the liquid of your choice
each hour and eat a salty food such as salted peanuts, potato
chips, or anything else that tastes salty.
HOW CAN YOU TELL THAT YOU NEED MORE SALT? Salt
deficiency causes tiredness, lethargy and cramps. It also
weakens muscles, causing you to slow down and lose strength.
If you suffer any of these symptoms, you can get a blood test
for sodium and chloride on the day after a hard workout. Low
blood levels of sodium are most likely to occur on the morning
after you have replaced fluid lost from heavy exercise. If
your blood sodium level is below 130, you are deficient and
need to add more salt to your food.
WHO IS MOST LIKELY TO SUFFER FROM SALT DEFICIENCY?
Vegetarians and people who limit meat are at increased risk
for salt deficiency because plants are naturally low in salt.
Meat, fish and chicken naturally contain far more salt. Most
processed foods are high in salt because manufacturers know
that salt makes food taste good and is also a preservative.
WHY DON'T CASUAL EXERCISERS SUFFER FROM SALT
DEFICIENCY? The North American diet typically contains up to
10 times the minimal daily salt requirement. If you doubled
or tripled your salt loses through sweating, you may still not
be deficient because you probably take in far more salt than
you need.
DOES EXTRA SALT CAUSE HIGH BLOOD PRESSURE AND HEART
ATTACKS? A review of the world's literature shows that salt
restriction does not lower high blood pressure for most people
with high blood pressure (9). Eating salty foods and drinks
when you exercise for more than two hours is unlikely to raise
blood pressure. I found only six long-term follow-up studies
of salt intake and heart attacks. Three studies suggest that
very low salt intake may cause heart attacks.
EXERCISE CAN PREVENT A RISE IN BLOOD PRESSURE WITH
EXTRA SALT INTAKE: Excessive intake of salt causes high blood
pressure in some, but not all, people. High blood pressure
increases risk for heart attacks, strokes, and kidney damage.
Many middle-aged people who start an exercise program lose
their tendency to develop high blood pressure when they take
in extra salt (10). This study shows that many people who
develop high blood pressure from a high-salt diet when they
are sedentary, will not develop high blood pressure on the
same diet when they exercise.
PEOPLE WITH METABOLIC SYNDROME ARE THE ONES MOST
LIKELY TO DEVELOP HIGH BLOOD PRESSURE FROM EXCESS SALT INTAKE:
A high-salt diet causes high blood pressure most commonly in
people who suffer from metabolic syndrome and are pre-diabetic
or diabetic (11). Metabolic syndrome occurs when cells lose
their ability to respond adequately to insulin and blood
levels of sugar rise too high. It is caused by eating too much
sugar and other refined carbohydrates, being overweight, not
exercising, and lacking vitamin D. Metabolic syndrome is
characterized by storing fat primarily in the belly, having a
thick neck, high blood triglycerides, low blood good HDL
cholesterol, high blood sugar, and eventually liver damage and
all the side effects of diabetes. People with metabolic
syndrome have a greater rise in blood pressure with increased
salt intake and a drop in blood pressure with salt
restriction.
BUY A BLOOD PRESSURE CUFF: If you are concerned about
your blood pressure, you can buy an inexpensive wrist cuff and
check your systolic blood pressure at bedtime. If it is below
120, you probably do not need to worry about salt. If it is
above 120, and particularly if you store fat primarily in your
belly rather than your hips, your good HDL cholesterollis below 40,
your triglycerides are above 175, or you have a blood sugar above
100 two hours after a meal or an HBA1C above 5.9, you probably
should restrict salt and definitely should work to correct the
causes of metabolic syndrome:
*lack of exercise,
*overweight,
*eating too much red meat,
*taking sugared drinks and foods,
*lack of vitamin D, and
*not eating enough fruits and vegetables.
SUMMARY: If you do not exercise, you do not sweat
very much and you do not need very much salt. Too much salt
can increase blood volume which raises systolic blood
pressure. Being fat is the primary cause of elevated diastolic
blood pressure. On the other hand, if you exercise
vigorously, you sweat tremendously and lose a lot of salt.
Without the extra salt that you need, you will not recover
from your hard bouts of exercise and you will be more likely
to be injured and tired all the time.

References:
1. Medicine and Science in Sport and Exercise
1999(October);31(10):1406-13
2. American Journal of Emergency Medicine, 1999;17(6):532-539
3. British Journal of Sports Medicine, August 2003
4. Medicine and Science in Sports and Exercise, January, 2007;
and Clinical Journal of Sport Medicine, January 2007
5. J Sports Sci 2007:15:297-303
6. Eur J Appl Physiol 1996:73:317-325
7. Clinical Autonomic Research, 2002;12(5):353-357
8. American Journal of Hypertension, 2001;14(7, Part 1:653-659
9. Journal of Hypertension. May 2011;29(5):821-828
10. Journal of Human Hypertension, May 2006
11. Lancet, published online March 2, 2009