WebExercises® Forum

Exercise in the Sun - Got Water?

2007-09-01T13:08:00.000-07:00

If you enjoy exercising outdoors during summertime, forgetting to stay hydrated can be hazardous to your health. Does that mean that you should give up exercising outside during the long, hot summer? Absolutely not! However, you do need to become better informed about how to safely be physically active outdoors when it’s hot, even if you don’t think you’re exerting yourself.

The human body is made up of 50-75% water which in hot weather may become dehydrated causing you to lose as much as 6% of body weight increasing the risk for heat stroke. Therefore, 1 to 2 cups of fluid is recommended for every 15 to 20 minutes of exercise or activity. Your exercise should not be thought of as only on the sports field. Risk of dehydration from physical activity may be on the trial hiking, golf course, or in the garden.

However for athletes, maintaining hydration is that much more important since a loss of 1-2% of body weight during exercise has been shown to adversely affect performance.

Children are particularly at risk to dehydration since they don't adapt as well as adults do to exercise in hot, humid weather. According to MayoClinic.com “They produce more heat, sweat less and may be less likely to drink enough fluids during exercise — all of which increase the risk of dehydration.”

According to research, the best time to hydrate is prior to exercise whether it is short duration, high intensity, or prolonged endurance activities. The recommended fluid intake is 8 to 16 fluid ounces prior to exercise. To avoid overloading your system, it is suggested 12 to 18 ounces be ingested 2 hours before exercise to allow your renal system enough time to properly process and regulate the fluid.

Although water is generally a great source of hydration, one study showed that the thirst mechanism shuts down at 68% of hydration when water alone was used. When sodium was added to the solution, hydration was increased to 82%.

If involved in prolonged exercise or endurance training lasting longer than 45 minutes, fluids containing 6-8% of carbohydrate (e.g. Gatorade, Powerade, AllSport) has been shown to effectively delay fatigue and improve performance. The form of carbohydrate that should be used is either glucose or sucrose. This may also improve coordination and reaction skills since your brain function is dependant on your glucose levels.

Body builders and overweight people tend to be more susceptible to heat related illnesses due to there increased body mass.

If an inadequate amount of fluid replacements are not ingested, heat related illness might occur. Some warning signs of this include:

· Headache · Weakness · Nausea · Cramps · Mental Slowness · Unsteadiness · Visual Disturbance · Faintness · Fatigue · Chills · Rapid Pulse · Dizziness

If you experience any of these symptoms, stop the activity immediately, rest and rehydrate in a cool environment. If the symptoms persist or worsen, seek immediate medical attention.

To prevent the chance of heat illness, wear clothing that exposes as much skin surface as possible to encourage sweat evaporation. This is the body’s natural temperature regulator. Choose material such as cotton that will bring sweat to the surface allowing evaporation to take place. Materials that to not “breath” and that are impermeable to water will increase the risk of heat illness.

With a little preparation and a few precautions, you can stay healthy and enjoy your favorite outdoor activity during the long days of summer.

References available by request.

Does Lactic Acid Cause Muscle Soreness?

2007-08-28T11:55:00.000-07:00

There is belief among athletes and active people that lactic acid is responsible for delayed onset muscle soreness (DOMS), or the general muscle soreness experienced 1 to 2 days following intense exercise. However, this is not the case.

Lactic acid is produced in our body as we break down glucose or glycogen (what our muscles use for energy) during exercise. This lactic acid production is what’s responsible for the burning sensation we experience in our muscles during high intensity exercise.

The accumulation of lactic acid can be attributed to a few reasons including low muscle oxygen and the recruitment of fast twitch muscle fibers.

First, as our exercise increases to a high intensity, we are unable to take in and process enough oxygen for our working muscles. This lack of sufficient oxygen is termed anaerobic exercise. If the exercise is to continue at this level we will soon reach a point where our blood lactic levels are high and our glucose/glycogen are low leading to muscle fatigue.

Second, our muscles are made up of slow and fast twitch fibers. Slow twitch muscle fibers are used for endurance activities such as long distance running. Conversely, fast twitch fibers are used for explosive activities including jumping and sprinting. Fast twitch fibers contain enzymes that promote the formation of lactic acid at a quicker rate as compared to slow twitch fibers. Therefore, when we engage in exercises that use these fast twitch fibers our lactic acid levels raise.

Upon accumulation of lactic acid in the blood, studies indicate levels return to a resting level within 60 minutes following exercise. Therefore, it is unlikely lactic acid is responsible for DOMS 1 to 2 days after high intensity exercise.

How can we speed the removal of lactic acid from our blood? This can be accomplished by engaging in continues light activity or a “cool down” period immediately following the intense exercise. Research shows blood lactic acid returning to resting levels within 40 minutes with light exercise as opposed to near 60 minutes without light exercise.

If lactic acid is not responsible for muscle soreness, then what is the cause? Recent evidence indicates this soreness arises from microscopic injury to muscle fibers. This initiates biochemical-healing response characterized by inflammation and edema within the injured muscle. Since this series of events takes place slowly, the resulting pain does not become evident until 1 to 2 days after intense exercise.

How do you avoid DOMS? DOMS usually occurs when an exercise uses muscles unaccustomed to performing the activity. Therefore, initiate any new exercise gradually avoiding high intensity during the first 5 to 10 training sessions. This will allow your muscles to adapt slowly and reduce the incidence of DOMS. However, if the pain persists longer than 1 week or progressively worsens, consult your personal healthcare professional to evaluate your condition.

References available by request.

An Asprin Before Training May Keep The Strength Gains Away.

2007-08-27T23:39:00.000-07:00

Athletes and weight lifters alike occasionally turn to non-steroidal anti-inflammatory drugs (NSAIDs) as a way to decrease delayed onset muscle soreness (DOMS). What they don’t realize is this may be keeping them from increasing their size and strength.

NSAIDs are most commonly purchased over-the-counter in the form of Aspirin, Acetaminophen (Tylenol), and Ibuprofen (Advil) as a way to decrease pain and inflammation following an injury. When we sustain an injury our body responds by sending white blood cells to the injury site and producing many chemicals necessary for the healing process. Some of these chemicals are called prostaglandins. It is these prostaglandin’s that help regulate the inflammation process. Along with this regulation they also stimulate pain receptors causing us to experience pain. NSAIDs work by inhibiting prostaglandin’s, resulting in reduced pain and inflammation.

Many athletes and weight lifters turn to NSAIDs as a way to improve performance by decreasing DOMS and shortening their recovery time of muscle soreness. According to the latest research, the effectiveness of this is controversial. Four of nine studies found a particular NSAID to be effective in reducing pain levels of DOMS while the other five studies did not. Additionally, athletes who suffered from DOMS and ingested NSAIDs reported a shorter recovery period ranging from three to ten days. This was measured with 1-rep max leg extension exercises.

However, this shortened recovery was found in the same studies that reported decreased muscle soreness. Therefore, this improvement can be attributed to the lack of muscle soreness.

Will NSAIDs help my strength training if they reduce DOMS and improve recovery time? Not if muscle strength and growth is important to you. First, NSAIDs have been shown to inhibit protein synthesis (making new protein) after weight training exercises. In one study, protein synthesis was shown to be elevated by more that 75% twenty-four hours following resistance training. This protein synthesis is what is responsible for muscle becoming stronger and bigger. In subjects who took NSAIDs, protein synthesis was not elevated at all.

Second, NSAIDs have been shown to delay muscle regeneration in animals. Muscle regeneration and repair is important following heavy resistance training where eccentric or negative repetitions are emphasized. This resistance training causes microscopic injury to muscle fibers that needs to be repaired. Delaying this repair does not allow the muscle to become stronger.

NSAIDs do not need to be completely avoided. They are effective for acute injuries helping to reduce pain and inflammation. However, they should be used judiciously. Long term or chronic use may lead to gastrointestinal and kidney problems. Consult your healthcare professional for additional questions.

References available by request.