Wednesday, December 13, 2006

Sleeping Helps You Lose Weight

Good news. Sleeping can help you lose weight! Recent research in the US has found how sleep can influence your appetite. Sleep should be seen by all of us as an important aspect of our health and fitness programmes/lifestyle and this article highlights just one important reason as to why.

Sleep Off Excess Weight
"Okay maybe it’s not so simple, you still have to control calories and exercise to stay in shape. But now, medical evidence suggests that getting a good night’s sleep can also ward off those extra pounds.
A recent study discovered that a lack of sleep alters the levels of these hormones that affect the appetite:
Ghrelin: produced in the gastrointestinal tract, triggers hunger
Leptin: produced in fat cells, sends a signal to the brain when you’re full
Researchers at the University of Chicago found that when sleep is restricted, leptin levels go down (the brain doesn’t get the signal that you’re full) and ghrelin levels go up (appetite is increased). Not only do appetites increase, the desire for high-carb, calorie-dense foods increases by 45 percent.
“The study provides biochemical evidence connecting the trend toward chronic sleep curtailment to obesity and its consequences,” said Eve Van Cauter, Ph.D. and professor of medicine at the University of Chicago.
Another study, this one at the University of Wisconsin Medical School, showed a relationship between the same hormones (leptin and ghrelin) and weight gain. The analysis concluded that people who slept for shorter periods had reduced levels of leptin and elevated levels of ghrelin.
These findings help explain what many have already observed: people who habitually sleep less than eight hours per night have higher body mass indices (BMI) than those who sleep more.
BMI is the ratio between weight and height. In general, except for people who are extremely muscular, a high BMI is an indicator of excess weight and susceptibility to certain diseases such as cardiovascular disease and adult-onset diabetes.

How much sleep do we need?
Unfortunately, sleep deprivation is now a way of life. According to the National Sleep Foundation, sleep duration among American adults has decreased by up to two hours a night since the 1960’s. In 2002 more than 37 percent of young adults said they slept less than seven hours per night, compared to about 16 percent in 1960.
Besides the effect of sleep on hormones, which in turn can make you gain weight, a lack of sleep can weaken the motivation to select nutritious foods. And when you’re barely getting by on a few hours of sleep, you’re less likely to exercise!
Many experts say adults need a minimum of seven to nine hours of sleep a night. To get more sleep, the American Academy of Family Physicians suggests the following:
Go to sleep and wake up at the same time every day, even on weekends
Develop a bedtime routine, such as taking a warm bath or reading for ten minutes
Don’t use your bedroom for balancing your checkbook or watching television
Make sure that your bedroom is quiet and dark
When you set your weight loss or fitness goals, don’t forget to factor in a good night’s sleep!

I hope you enjoyed this article and remember - have a good nights sleep.
Steve

Tuesday, December 05, 2006

Exercise Duration for Maximum Fat Burning

I often have the question asked - "How much cardio work do I need to do to burn fat?"

The answer is - "As much as you can." (Within safety and injury/overuse boundaries, of course.)

The table below depicts the percentage of fat used as an energy source (compared to carbohydrates) over time.





Note that at 30 minutes of exercise about 60% of your energy is sourced from carbohydrates while fat supplies about 40%. At the 2-hour mark, energy is sourced at a ratio of 50%-50% and as exercise time increases fat is used more and more as the primary source of energy.

So, the longer you can exercise at a moderate intensity, the more fat you are going to burn. Of course extended periods of exercise (greater than 2-hours) is going to be difficult for most people to undertake. However, the important thing to note is that even at 30 minutes you are sourcing about 40% of your energy from fat. So, get moving (for at least 30 minutes) for as long as you can to maximise your fat burning.

Enjoy your exercising!

Steve