Dramatic Health Benefits After Just One Exercise Session!

[Guest guest]

Dramatic Health Benefits After Just One Exercise Session

New research shows that just one session of exercise can prevent a

primary symptom of type 2 diabetes by altering fat metabolism in muscle.

Researchers from the University of Michigan discovered that a session

of aerobic exercise increases storage of fat in muscle, which actually

improves insulin sensitivity. Low insulin sensitivity, or insulin

resistance, is an impaired ability of the body to take up sugar from

the blood, which can lead to high blood sugar and diabetes.

Horowitz, associate professor in the U-M Division of

Kinesiology, and his former doctoral student, Simon Schenk, now a

post-doctoral fellow at the University of California, San Diego,

conducted the study, which appeared online May 17 in the Journal of

Clinical Investigation.

" It's long been known that exercise can greatly improve insulin

sensitivity, " Horowitz said. " But how exercise improves insulin

sensitivity in obesity, and how much exercise is necessary for this

effect is not clear. "

Impaired insulin sensitivity is particularly a problem in obese people

because of the excessive amount of fatty acids released from their

body fat stores. This overabundance of fatty acids is taken up by

tissues like muscle and liver where they interfere with the ability of

insulin to regulate sugar metabolism.

In muscle cells, fatty acids can be burned for energy, and they also

can be stored as intramuscular triglyceride, or IMTG. IMTG is a

reservoir for fat storage, and high IMTG levels correlate with insulin

resistance in obese people and those with type 2 diabetes. Partly

because of this correlation, many researchers assumed IMTG is somehow

involved in the development of insulin resistance. Yet, people who

exercise regularly also have high IMTG levels, but they are actually

very sensitive to insulin.

With that in mind, U-M researchers set out to test their novel

hypothesis: that increasing the capacity for fat storage in muscle

after one session of exercise can actually increase insulin

sensitivity. They suspected that for several hours after exercise more

fatty acids entering the muscle will be stored as IMTG, thus keeping

them from turning into more harmful metabolites that are known to

cause insulin resistance. Essentially, this means that exercise may

cause you to store more fat in your muscles, but in doing so your

insulin sensitivity improves.

Researchers studied eight LEAN female subjects and infused fat into

their bloodstream to increase fatty acid to levels commonly found in

obesity. The subjects were admitted to the hospital for this two-day

procedure on two separate occasions. On the first day of one hospital

stay, they exercised for 90 minutes at 75 percent of maximum

heart-rate; on the other visit, they remained inactive.

With all other conditions being equal, researchers found that during

the nonexercise visit, the fat infusion reduced insulin sensitivity to

levels commonly found in obese people.

However, they found that during the exercise visit, not only did the

exercise prevent the impairment in insulin sensitivity, but it

increased insulin sensitivity by about 25 percent over their base

levels. The researchers also found that the exercise session had

diverted more fatty acids to be stored as IMTG than without exercise,

and as a result fewer fatty acids were available to become the harmful

metabolites known to impair insulin sensitivity.

" We believe this describes a primary mechanism for how exercise

improves insulin sensitivity in obesity, " Horowitz said.

The study findings also highlight the important metabolic health

benefits of a single exercise session.

" Some of the key health benefits of exercise are not related to

improved fitness but instead, the residual effects from the most

recent exercise sessions are most important, " he said.

If this is correct, then getting a regular so-called dose of exercise

may be much more important than your level of physical fitness. How

hard the exercise dose must be in order for an obese person to reap

the benefits, and how long the effects last remains unknown. Horowitz

and his research team are addressing these issues.

Note: This story has been adapted from a news release issued by

University of Michigan.

[Guest guest]

bill4cr wrote:

>

> New research shows that just one session of exercise can prevent a

> primary symptom of type 2 diabetes by altering fat metabolism in muscle.

>

Doesn't surprise me.

Sports physiology people have known for years that the major reservoir

for glycogen (polymerized glucose, the production of which is triggered

by insulin) is in the muscles. A basic principle of sports nutrition is

to fill that reservoir up before training or an event; it's believed

that your muscles are particularly ready to store glycogen after a

workout, so it's good to eat an appropriate amount of carbohydrates a

few minutes after working out.

I think it's just common sense that a person whose glycogen reservoirs

are full is going to be insulin resistant -- they just aren't going to

have any place to store glycogen, so the major pathway of reducing

blood sugar is blocked. A person who eats a lot and isn't active will

get in trouble, which can be avoided by eating less or being more active.