While lying around this evening wishing I could sleep, I got to thinking about various topics related to muscles and metabolism…
In particular, since it was so damned warm, and I was sweating in proximity to some larger muscle groups, I got to thinking about how temperature increases blood flow and whether or not it would be a very cheap way to increase metabolism.
[i]The present work was aimed at measuring intramuscular oxygen consumption (O) as a function of temperature (T), in human forearm, during rest and aerobic isometric exercise (4% of the maximal voluntary contraction, MVC). Based upon results from in vitro experiments performed on isolated mitochondria of animal species, it was hypothesised that, during isometric exercise, the O-T curve should display a maximum for some ‘optimal’ T. Intramuscular T and measurements were performed using a combined deep body temperature/near infrared probe during muscle cooling. At rest, O increased non-linearly and monotonically as a function of T (n=8). increased ~2 times when going from 26 to 36C. A log()O-T plot or a log()O-1/T did not linearise the data.
During isometric contraction, O values at 26.8+/-0.6, 28.6+/-0.9, 31.9+/-0.9 and 35.9+/-0.9C were 3.04+/-1.26, 7.60+/-1.64, 4.43+/-1.95, and 6.64+/-1.37 mol 100 g−1 min−1, respectively (n=6). The O value at 28.6C was significantly higher (P<0.05) than that at 26.8 and 31.9C. The ‘sudden’ O change at 28.6C is compatible with the phenomenon observed at the mitochondrial level.[/i]
However, I really don’t know how different muscle temperatures are from core body temperatures in a resting state. If they do differ fairly significantly, than it would be easy to dress warmly and increase muscle temperature up to core body temperature.
At little Googling yields this snippet from some course material though, which is promising:
[i]There are 3 thermal zones:
superficial zone - skin and subcutaneous tissue
intermediate zone - skeletal muscle mass
deep zone - contents of cranial, thoracic and abdominal cavities.
It is only in the central parts of the body that the tissue temperature is kept high and relatively constant. The periphery of the body has a lower tissue temperature.
Or even this one…
[i]At rest there is a temperature distribution in the body and circulation.
1.Blood leaves the heart at about 37?C.
2.As it travels to the extremities, the temperature falls as much as 15?C or more without the subject feeling particularly cold.[/i]
And further in the same set of lecture notes…
[i]Heat loss is largely dependent upon the temperature difference between the body and the environment.
a.The heat exchange between the core and the skin largely controls skin temperature over the range 20 -28?C in ambient temperature.
b.Vasoconstriction and vasodilation by the sympathetic nerves can vary the skin surface between 21 and 29C.
c.Below 20C, internal heat production is increased.
d.Above 28C, sweating is used for increased heat loss.[/i]
Hmmm… a lot of muscle is obviously close to the skin.
Stretching was another strategy that came to mind. Anecdotally, people have stated that stretching is similar to exercise in some respects. It is known to prevent muscle wasting in the ill, for example.
A more general study, which may or may not be applicable shows that heat and stretching both have interesting effects on muscle tissue.
Effects of heat stress, mechanical stretching or a combination of both on the expression of heat shock proteins (HSPs) and total protein level were studied in a culture system. Rat skeletal muscle cells (L6) were cultured on flexible-bottomed culture plates. They were subjected to one of the four following conditions: (1) 97 h incubation at 37 degrees C, (2) 1 h incubation at 41 degrees C followed by 96 h incubation at 37 degrees C, (3) 1 h incubation at 37 degrees C followed by 96 h cyclic stretching (18% of initial length, 2-s stretch and 4-s release) at 37 degrees C or (4) 1 h incubation at 41 degrees C followed by 96 h cyclic stretching at 37 degrees C. The expression of HSP72 and HSP90 and total protein was determined in the crude homogenates, supernatant and pellets. Cellular protein concentrations in the homogenates and pellets were increased by heat stress and/or mechanical stress (stretch). A cumulative effect of the combination of heating and stretch on the protein concentration in the homogenates and in the pellets was noted. The expressions of HSP72 and HSP90 in the pellets were also increased by heat stress and/or stretch. However, HSP90 in the supernatant did not change following heat stress and/or stretch. The regulation of HSP72 and HSP90 expression in skeletal muscle cells may be closely related to total protein, the abundance of which is also stimulated by mechanical and heat stresses. These observations suggest strongly that heating and passive stretch of muscle may be useful as a means of increasing muscle mass, not only in athletes but also in patients during rehabilitation.
Also, I remember reading on this site somewhere some hints on achieving optimal muscle growth. One of those hints was to keep the muscles warm. I also recall a perhaps more recent article dealing with “Stretch Mark Mass” which talks about muscle growth via stretching and the importance of muscle volumization (stretching) as well.
So, where does this all lead, other than to me wishing I was asleep right now? To some questions or possible strategies.
What would be the effect of being on a below maintenance calorie diet, consuming HOT-ROX and ensuring that you keep all the major muscle groups closer to core temperatures? The percentage resting O2 consumption increase described above is huge! No, let me put that in perspective, it is HUGE! Can we actually take advantage of some of that? Would HOT-ROX help ensure optimal fat utilization during increased muscle metabolism?
Would non-specific stretches throughout the day also aid in raising muscle metabolism or growth/anti-catabolism?
Is there some type of synergy to be obtained between various strategies involving workouts, nutrition, stretching and temperature control? For example, you probably don’t want to increase metabolism during a fasted or catabolic state.
Anyway, time for me to get some sleep… I wonder if these thoughts will be interesting under the light of day?