Cyclingnews Fitness Q&A - February 24, 2011

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Training in high heat

Hi guys,

I understand this may not be a timely question for those in the northern hemisphere, but what do you know about training in the heat?

I went for a ride in the heat the other day (it was around 37 celcius) and found my heart rate was a few beats per minute higher than usual and average speed was a couple of km's per hour slower than usual. The ride was on a regular route so any differences in my performance are obvious to me.

My understanding is that in the heat my body is working harder even though my quantitative performance might be lower, is this correct? and why is this so?

Can you get used to training in the heat to a point where its possible to perform equally in heat and in 'ideal' conditions?

Thanks in advance,
Tom K

Scott Saifer says:


Your experience of higher heart rate and lower power or speed when training is extreme heat is normal. It is possible to acclimate to heat enough to reduce the impact of riding in heat, but you will always perform better in pleasant weather (hight teens Celsius, 60s Fahrenheit) than in temperatures much warmer than that.

Here's the physiology: Your body can shunt blood to different places according to where it is most needed. Your brain always gets it's needed share. When you are resting, a bit of blood goes to your muscles just to keep them alive, and a bit goes to your gut, to keep it alive.

If you've eaten recently, more blood goes to your gut to support peristalsis and absorb the nutrients absorbed during digestion. The heart always gets the blood it needs to support it's pumping, since otherwise it doesn't pump. As you start to exercise, your muscles need more oxygen and fuel, and need to dump more CO2 and waste heat. Blood is directed to the muscles and away from the digestive system.

If you are untrained, you have enough blood volume to support your brain and your muscles, but only by almost completely shutting down any blood flow to your gut. That's why beginners get nauseated if they try to eat while exercising. The food will sit as the muscles needed to keep it moving along won't be doing their job.

One of the effects of endurance training is to increase blood volume, particularly by increasing the volume of plasma, the liquid part of blood. That's why better trained athletes begin to be able to eat and digest while riding.

Blood has one more job we haven't discussed yet: All that waste heat that is being carried away from the working muscles needs to be dissipated into the environment or the body overheats and stops functioning efficiently. To do that, the body shunts blood to the skin where radiation and evaporation of sweat can remove heat.

In order to supply blood to the skin, it has to be shunted away from muscles, so on the hotter the day, the less blood goes to the muscles at the same heart rate. To some extent, heart rate can increase so you can maintain normal power so long as that power is well below your cool-day peak, but that effect is limited. Any sustained, aerobic power that is near your LT on a cool day will be above your limit on a hotter day simply because your ability to deliver oxygen to your muscles is compromised by the need to deliver it to your skin for cooling.

Now you can probably understand why eating while riding becomes more challenging on hotter days, even for well trained athletes. Blood volume may be enough to support digestion and muscular work, but not enough to support digestion, muscular work and cooling. Endurance training in the heat will cause a further increase in plasma volume beyond that caused by endurance training in pleasant weather, but won't be enough to completely negate the effect of heat on performance.

There is one more important effect to discuss that would prevent you from performing as well on a very hot day as on a cooler day, even if you could pump enough blood to deliver normal amounts of oxygen to your muscles at all work rates: Your brain doesn't want to be boiled. Your brain only works well in a narrow range of temperatures, and completely fails (you die) if you get outside that range, so your brain has evolved some very effective safety mechanisms for keeping your core temperature in that good range.

One of the mechanisms works like an amplifier on signals from your cortex to your muscles. On a cool pleasant day, it passes those signals along at full strength, but as core temperature rises beyond the 37 about 38-39 degrees, it starts to tamp down the signal. That means you have "try harder" mentally to get the same signal to the legs.

You feel like your are pushing harder to generate the same speed, or you go slower for the normal effort. You can overcome this effect to some extent by making the harder mental effort, but as core temperature rises with harder work, the tamping down of signals to the muscles becomes more extreme and there is an upper limit to how hard an effort can be sustained.

So, to answer your question briefly: Your experience of being slower on hot days is normal. You can train to reduce but not eliminate the impact of heat on performance.

Training in the heat, because you are making less power, is less effective than training in more pleasant conditions, so do a bit of heat acclimatisation training, but do the majority of your training in the early morning before the heat of the day. Note that you can acclimate to heat by exposure to heat, on or off the bike, and that exposure to cool undoes the effect, so dress warmly if you'll be in air-conditoned spaces in the summer. (That's one reason you see pros wearing sweaters and hats on days when you'd think they really ought not to need them).



After reading of Taylor Phinney's tendonitis issues and dealing with this issue myself what precautions can a cyclist take to avoid tendonitis? What is tendonitis and what are the causes for cyclists?

I usually have knee issues a month after starting my official training season (late January through February). Most likely too much volume too soon but the knee pain is not consistent enough to point the finger at volume.

Usually during January or February I experience some sort of knee pain that moves around my left knee. Sometimes riding regularly makes me feel better as well as icing /heating after rides. I have heard that a typical rider shouldn't increase their volume by more than 10 percent each season to avoid injury.

While this may be true for myself I find that it takes me months to build up volume to avoid knee pain. Is there any trick to hit the ground running when the training season begins? Every year my volume starts out at around 8-10 hours a week which I consider on the low end of the spectrum for someone who has been riding and racing regularly for over 6 years.

Another strange occurrence is knee pain when I don't ride frequently enough. If I skip a day or two my knee starts to feel sore as if scar tissue has built up in a matter of days. If I push through the pain by the end of a ride the pain is gone so my assumption is that I am clearing scar tissue. Could this be the case?

If I ride 30-60 minutes each day I feel the pain decrease day-to-day versus staying off the bike. After a few days of riding 30-60 minutes on the trainer the pain subsides and I can resume my normal riding. What do you make of this?

Also since this occurs only when it is the dead of winter I wonder if the cold could be exacerbating my already tender knee. Is there any validity to this theory? Cold weather = less circulation = knee pain?

I appreciate your help,


Scott Saifer says:


There are many different causes of knee pain. The secret to pain-free knees is to avoid all the causes. Briefly, knee pain can be caused by

1) Poor bike fit or and especially by problems of saddle height, arch support and wedging

2) Cold knees (keep the knees as warm as they would be bare on a 70F (21C) day. That means wearing several layers on cold days. The common wisdom is that poor circulation on cold days causes knee pain, but I don't know that anyone has ever proven that. I do know that many people with frequent knee pain in winter can clear it up by keeping their knees warm.

3) Too rapid build up of volume. You are right that 8-10 hours is not that much riding in a week, but it's a lot for someone who has been off the bike for several weeks or more. Try maintaining 3-4 hours per week of pedaling during your rest period, or starting from a week of half-hour rides if you take a long break. In either case, add only an an hour per week if your knees are giving you any trouble, and only two hours if they aren't. You'll soon enough be up to real volumes again.

4) Mashing big gears too soon. Spin with minimal pressure on the pedals for your first 3-4 weeks back in the saddle. Add pressure on the pedals only after you can do your 10 hours or more per week with no knee complaints.

5) Need for stretching: Lots of different muscles affect how the knee moves and how the knee cap tracks. Any one of them being tight can cause knee pain. Routinely stretch at least quads, hams and sartorius.

Steve Hogg says:

Just a postscript to Scott's comprehensive answer. Jonathan, you asked why your knee gets sore when you don't ride for a few days and comes good when you start riding again. Your VMO is the likely culprit. Your VMO is the inner head of your quadriceps.

Unlike the other quads, the muscle fibre orientation of the VMO is oblique meaning that it is the prime muscular lateral stabliser of the knee. Unlike every other muscle in the body (except one small ankle muscle that I forget the name of) the VMO will lose strength significantly after just a few days of inactivity. I've done a bit of research on this and my best guess (and that is all that it is) is that the lateral orientation of the fibres is a relatively recent evolutionary acquisition.

To your case; based on what you say, something about your gait or footplant doesn't allow you to use your VMO well and that you have a tendency towards instability at the knee. Once on the bike, you are still unstable to some degree (pain) but the action of riding loads your VMO, strengthening it and improving your knees stablity. The initial soreness is likely to be a weak VMO being forced to work again. The pain disappears as more riding equals stronger VMO equals more stable knee.

So tell your wife that you need to ride your bike more often... It works for me. A personal example of the benefit of strong VMOs: I have a severely unstable left knee from a teenage accident. To counter this I have developed very large VMOs relative to the rest of my leg muscle development. While ever I ride regularly I can do anything on my dicky knee including a lot of things that I am not supposed to be capable of with the damage I have.

However, if I don't ride for a month, for example, I start to have trouble walking up and down steps and it takes a week or two of riding to regain adequate knee stability. So the message is to keep riding your bike.

Well developed VMOs are a must for pain free, intense cycling.

Red wine

I have heard from a few different people that Red wine is quite beneficial for cyclists and that a pro wouldn't survive a grand tour without a glass at night (not a few beers after curfew, a singular red wine).

The reason this conversation came up was because I made a new years resolution not to drink this year one of the reasons being to help me with my cycling. Would it infact be more beneficial to have the occassional drink, not in excess I do know thats bad for more things than just cycling.


Scott Saifer says:


There are plenty of successful teetotaling athletes in cycling. A small evening glass of red wine helps some athletes relax. Others find other ways.

Red wine contains resveratrol, a chemical thought to be beneficial to health and longevity in a number of ways. Compounds with similar effects are found in a variety of other foods. Non-drinkers often find that even a small amount of alcohol interferes with recovery, but regular drinkers don't seem to have this problem.

Riders who are predisposed to alcoholism, that is, those who find it difficult to stop after one drink, should avoid wine and other alcohols entirely. If you can always stop after one glass, red wine won't hurt you. You may perceive some benefit, though there's no reason to think the benefit would be unique to red wine.

Thyroid issues

Dear fitness panel,

I am a 46-year-old male and have been training in cycling for 15 years, competing at single and multi-day open events in road and mountain biking. I weigh 75kg and stand 181cm tall. Also the past three years I have been running and participating at 10km and half marathon events. Usually I am logging between 4,000-7,000km of quality training per year.

In May 2010, after a condition of exhaustion and palpitations, I have been diagnosed with thyroid thyloma CA and had an operation in July 2010. Now, I have been stabilised and taking 175 µg T4 prescription. I feel fine, I've been jogging and cycling at a light volume and doing some intensity sessions. I am not sure how far I can return to my normal training and event participation. My doctor says to "live normally" but I know that sports at higher intensity than simple weekend activities are not what he means!

Any advice would be great for me! Thanks in advance.

Dimitris Servis
Athens, Greece

Scott Saifer says:


Dr Bethards may have some more detailed understanding to share with you, but from what I know, if you had your thyroid removed then you can exercise as hard as anyone else, provided that you get your T4 dose dialed in. That can take a lot of rounds of trying a particular dose, checking your blood levels and adjusting again.

The dose you need may also change with your exercise level, so you'll have to work closely with your doctor to figure out just how much thyroid to use. I have had several clients return to racing successfully once they've gotten their doses dialed in. They certainly were in no condition to race when the dose was either too high or too low though, so it took a while.

Chamois thickness


I recently purchased some knicks (by the same manufacturer) for training and racing that have differing chamois thickness and shape. The racing knicks chamois have 14mm high, 120 density foam at the contact area of the pelvic region whilst the training knicks have 8mm of high density foam. Both have mid level impact foam at the frontal region however the racing knicks chamois is shorter in the front section.

Being a relatively light rider (approx 58kg) would you suggest altering saddle height/angle for the racing knicks?



Steve Hogg says:

Great question. You have raised a subject that is a common problem but rarely mentioned. Yes, change your seat height to suit when you swap knicks. As an example, I have several pairs of quality knicks from a variety of manufacturers that all require the same seat height.

I also have one pair that were given to me as a present and they are made by a well known high end brand and have an unusually thick (at least by my standards) chamois. My body weight on the seat compresses this extra thickness to some degree, but unless I drop my seat post 3mm further into the frame than normal, I struggle on the hills or when riding big gears on the flat. I'm 18kg heavier than you so the effect is probably even more apparent for you than for me.

The Cyclingnews Form & Fitness panel

Scott Saifer ( is head coach, CEO of Wenzel and has been coaching cyclists professionally for 18 years. He combines a master's degree in Exercise Physiology with experience in 20 years of touring and racing and over 300 road, track and MTB races to deliver training plans and advice that are both rigorously scientific and compatible with the real world of bike racing.

Scott has helped clients to turn pro as well as to win medals at US Masters National and World Championship events. He has worked with hundreds of beginning riders and racers and particularly enjoys working with the special or challenging rider. Scott is co-author of Bike Racing 101 with Kendra Wenzel and his monthly column appears in ROAD Magazine.

Steve Hogg has owned and operated Pedal Pushers since 1986, a cycle shop specialising in rider positioning and custom bicycles. In that time he has positioned riders from all cycling disciplines and of all levels of ability with every concievable cycling problem. Clients range from recreational riders and riders with disabilities to World and National champions.

Kelby Bethards, MD received a Bachelor of Science in Electrical Engineering from Iowa State University (1994) before obtaining an M.D. from the University of Iowa College of Medicine in 2000. Has been a racing cyclist 'on and off' for 20 years, and when time allows, he races Cat 3 and 35+.

He is a team physician for two local Ft Collins, CO, teams, and currently works Family Practice in multiple settings: rural, urgent care, inpatient and the like.

Pam Hinton has a bachelor's degree in Molecular Biology and a doctoral degree in Nutritional Sciences, both from the University of Wisconsin-Madison.

She did postdoctoral training at Cornell University and is now an associate professor of Nutrition and Exercise Physiology at the University of Missouri-Columbia where she studies the effects of energy balance on bone health. She has published on the effects of cycling and multi-day stage racing on bone density and turnover.

Pam was an All-American in track while at the UW. She started cycling competitively in 2003 and is a three-time Missouri State Road Champion.

James Hibbard progressed from the junior to the professional ranks as a rider and has over 15 years of competitive cycling experience. He is a former Collegiate All-American track cyclist, trained as a resident athlete at the United States Olympic Training Center, earned international medals as part of the U.S. National Team, and was a member of the powerhouse Shaklee and HealthNet Professional road cycling teams.

He has earned 13 National Track Championship medals, as well as numerous junior, U-23 and elite California State championships on both the road and track. Since retiring from full-time racing in 2005, James has focused on his development as a coach.

David Fleckenstein, MPT, OCS ( is a physical therapist practicing in Eagle, ID and the president of Physiotherapy, PA, an outpatient orthopedic clinic focusing in orthopedics, spine, and sportsmedicine care.

His clients have included World and US champions, Olympic athletes and numerous professional athletes. He received his Masters degree in Physical Therapy from Emory University and is currently completing his doctorate at Regis University.

He is a board certified orthopedic specialist focusing in manual medicine and specific retraining of spine and joint stabilisation musculature. He is a former Cat I road racer and Expert mountain biker.

Carrie Cheadle, MA ( is a Sports Psychology consultant who has dedicated her career to helping athletes of all ages and abilities perform to their potential. Carrie specialises in working with cyclists, in disciplines ranging from track racing to mountain biking. She holds a bachelors degree in Psychology from Sonoma State University as well as a masters degree in Sport Psychology from John F. Kennedy University.

Dave Palese ( is a USA Cycling licensed coach and masters' class road racer with 16 years' race experience. He coaches racers and riders of all abilities from his home in southern Maine, USA, where he lives with his wife Sheryl, daughter Molly, and two cats, Miranda and Mu-Mu.

Dario Fredrick ( is an exercise physiologist and head coach for Whole Athlete™. He is a former category 1 & semi-pro MTB racer. Dario holds a masters degree in exercise science and a bachelors in sport psychology.

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