CCS, Telomeres and Gaucho fun

I guess this is more relevant to cell biology or physiology but I thought some of you may be interested in this article in the New York Times today that describes research published in the journal Circulation that demonstrates that physical exercise can actually keep your cells younger.

Cell 'age' was assessed by looking at their telomere length. Unless you've been living under a rock for the last year you are probably aware that telomeres are tiny caps on the end of DNA strands and the discovery of their function won several scientists, including CCS biology graduate, Carol Greider, the 2009 Nobel Prize in medicine.

The research looked at four groups of people: young and sedentary; middle-aged and sedentary; young professional runners in their 20s; and finally middle-aged longtime runners.

Cells in both the active and sedentary young adults had similar-size telomeres because when you are young none of your cells are old enough to have significantly shortened telomeres. But when they examined the middle aged groups they found a HUGE difference

In general, telomere loss was reduced by approximately 75 percent in the aging runners. Or, to put it more succinctly, exercise, Dr. Werner says, ‘‘at the molecular level has an anti-aging effect.’’

This study of course raises a lot of questions but it is really nice to have such a large effect and hopefully follow up studies will clarify how much exercise is required and for how long. The middle aged runners in the study were running an average of 50 miles a week and had a 35 year training history.

Anyhow if you want to stop your telomeres shortening you may need to start running now. Fortunately this Saturday sees the return of the UCSB Running Series. A good incentive to get out of bed and drag yourself around the lagoon a few times (and then eat pizza).

25mph

Not exactly the most surprising prediction but in a blog posting last year, Most obvious nickname ever..., I wrote:
'If there was a regular 140m or 150m event I imagine the world land speed record would be set over that distance.'

Unless I'm reading the wrong news sources the news that a human has just exceeded 25mph in an athletic event for essentially the first time ever has received remarkably little attention.

On a cold and rainy Sunday in Manchester, England, on a specially laid out 150m track on the streets Usain Bolt made it look easy. His time, 14.35 works out at 10.453 m/s or 23.38mph. even more impressively the final 100m of the 150m (ie a 100m with a flying start) was timed at 8.72. This works out to be 11.468m/s or 25.65mph.

Anticipatory Thermogenesis

Yesterday Claudia mentioned that although control of the autonomic nervous system is generally considered to be involuntary we can, in addition, actually consciously influence many of these systems.

Posting a reference to Tim Noakes yesterday reminded me of his recent work with Lewis Gordon Pugh, a British 'Environmentalist, Explorer and Swimmer.'

Pugh is most famous for his cold water swims which he usually does to publicize global warming and the melting ice-caps. These swims are done without a wetsuit, in water as cold as zero degrees centigrade (because of the salt seawater freezes a couple of degrees below zero).

An article in New Scientist magazine a few months ago reveals some of the science behind Pugh's remarkable ability. Most interesting was the discovery by his trainer, the aforementioned Tim Noakes, that Pugh is able to consciously raise his body temperature.

As the swim gets closer, he psychs himself up by listening to music by the likes of Eminem and P. Diddy. In the minutes before entering the water, Pugh recalls these emotions and is able to raise his core temperature, without doing any physical exercise, to 38.4 °C. That's an extraordinary 1.4 °C above his normal body temperature. Such "anticipatory thermogenesis" has been observed before, but not to such a high degree.

You can read the actual paper in the appropriately named 'Journal of Thermal Biology': Body temperatures during three long-distance polar swims in water of 0–3 °C.

Pugh appears to have reached some of the limits of the human body:

In 2007 he swam 1 kilometre in the coldest water yet - a glacial -1.7 °C - at the geographic North Pole.

"When I went below 0 °C the cells in my fingers started to freeze. It took another four months before I could feel my hands again," he says. After reaching his goal of swimming both in the Arctic and in Antarctica, Pugh has for now hung up his towel.

Muscle pain - four recent(ish) papers and one new class

A good question today about why your heart never aches after exercise - after all, a good bout of exercise works your heart just as much, if not more, than any other muscle.

There's a simple answer, the heart doesn't have the same type of pain receptors as the muscles, but a fuller answer is much more interesting and shows some surprising gaps in our knowledge.

There are two types of muscle 'pain' associated with exercise. There is fatigue during exercise, and we don't really know what causes that, and there is pain after exercise (DOMS or Delayed Onset muscle Soreness), and we don't really know what causes that! The cause of fatigue is a pretty hot topic. One theory is that it is caused by a problem with the calcium flow inside muscle cells. One of the functions of calcium is to help control muscle contractions. Recent research published in PNAS found that after extended high-intensity exercise, small channels in the muscle cells begin to leak calcium, which leads to weakened muscle contractions. This leaked calcium also stimulates an enzyme that attacks muscle fibers and also leads to fatigue. It is really surprising to me that such a basic phenomenon is still fairly unknown.

DOMS is thought to be caused by a breakdown of muscle fibers and microscopic tears in muscle tissue that occurs as a result of exercise. This typically occurs 1 to 2 days after exercise, particularly if the exercise is new or extreme. There is also evidence that DOMS is more extreme if the muscle movement is eccentric - that is the muscle elongates whilst under tension (eg lowering a weight, starting out with your hand by your shoulder and gradually lowering the weight will produce an eccentric contraction of the biceps muscle).

It used to be thought that lactic acid was involved in both these phenomena but recent evidence suggests that lactic acid may have been unfairly blamed for years and that it may play a more useful role.

In both these cases actual pain is probably caused primarily by swelling which puts pressure on nerves and produces the sensation of muscle pain.

Although the heart does not have the same type of stretch receptor that registers this type of pain it does have some pain receptors. Strangely enough it has the same type of nerve receptors that register the burning sensation from the capsaicin in hot peppers. These are the receptors that are thought to cause the sensation of chest pain from a heart attack. The heart may be less vulnerable to DOMS since it does not undergo eccentric contraction.

All of this is somewhat complicated by the role of the brain. Obviously it is in your interest to stop exercising before damage occurs to your muscles, and, in particular, to your heart. Tim Noakes, a South African sports scientist, has renewed interest in a rather old theory, that Noakes calls the 'Central Governor Model', that the brain is the primary organ that dictates how fast, how long, and how hard humans can exercise.

As you can tell I find this whole intersection of physiology and exercise very interesting. So I have bitten the bullet and next quarter (ie Fall 2009) I will be teaching a CCS class on Endurance Physiology. This will be a seminar format class where we read and discuss papers very much like those listed above and look critically at the evidence for and against various theories and the implications these have for the way people train for what I have generally termed endurance events (swimming, cycling, and running or, for those crazy enough, all three). Loosely inspired by the fact that for the first time in over 25 years Santa Barbara will have a large Marathon event in the fall of 2009.