Filed under: Exercise
The cool-down—a practice so engrained in our exercise habits that we assume it’s important. But, the truth is, the topic is understudied, and evidence for or against cooling down is still up for debate. What is a cool-down and what is it supposed to do? The American College of Sports Medicine (ACSM) recommends a period of low- to moderate-intensity aerobic or muscular endurance activities after exercise to gradually reduce heart rate and blood pressure and remove metabolic byproducts from the system. For some, this may be a slow jog down the street, or an easy ride around the block after a workout with the hope of also preventing delayed onset muscle soreness (DOMS). The long-standing theory behind cooling down was that it helped to remove lactic acid from the system, a substance that could later cause muscle aches and soreness. However, it is believed that DOMS is the result of minor muscle damage due to novel or intense exercise, but we do know that lactic acid is not the culprit. During cool-down—active recovery—more lactic acid is removed from the system than during passive recovery, i.e., no cool-down. But is this a good thing? In a study of cyclists, researchers found that when subjects stopped exercise abruptly, lactic acid turned into glycogen, a fuel for the muscles. But when the cyclists gradually tapered off activity, less glycogen was made, leaving less energy for the muscles. These results indicate that cooling down might not be beneficial and may waste useful energy for the muscles.
On the other hand, a cool-down lowers elevated heart rates faster than passive recovery does and may prevent post-exercise dizziness. Stopping abruptly after exercise can cause blood to pool in the dilated vessels of the legs and feet, which may lead to a feeling of light-headedness and/or dizziness. Keep in mind, however, that these symptoms can also be related to other post-exercise conditions such as low blood sugar, low blood pressure, dehydration, or even hyponatremia. If you experience these symptoms, check with your doctor to find out if there are other causes.
Scientists agree that cooling down is also beneficial for people with cardiovascular conditions and heart disease where the coronary vessels are narrowed due to atherosclerosis (fatty deposits), as blood return to the heart may be compromised without it.
ACSM currently recommends at least 5-10 minutes of cool-down, with at least 10 minutes of stretching after exercise. However, more research is needed to determine the value and ideal recommendations for cooling down. If stopping exercise abruptly causes symptoms of light-headedness and dizziness, then a cool-down is a good idea.
The Navy Operational Fitness and Fueling Series (NOFFS) is an important training program for sailors and Navy health professionals, combining sports science and injury prevention information to promote optimal human performance. The exercises in the series have been designed to train sailors for the types of activities they can expect to perform during operational duties. The NOFFS program is currently available as an app for iPhone, with on-the-go reference and training assistance right at your fingertips. The app features pictures, videos, and step-by-step exercise instruction, as well as nutrition tips and information. Download the app for free from the iTunes App Store!
It’s been commonly thought that exercise can ward off the effects of sleep loss, but it turns out that exercise only mitigates sleepiness and fatigue for an hour and doesn’t seem to have any effect on boosting performance throughout the day. Although regular exercise—both strength training and high-intensity endurance—does help you sleep better, it can’t replace lack of sleep—only actual sleep will do that. The loss of sleep affects physical performance primarily by reducing your motivation to exercise—so, when thinking about your workout plan for the week, include a plan to get enough sleep.
For information on how to improve the quality and length of your sleep, check out HPRC’s Mind Tactics Sleep Optimization section. For information on how sleep loss impacts other areas of fitness, check out the HPRC’s Total Force Fitness article The impact of sleep loss on total fitness, and for information on physical fitness check out HPRC’s Physical Fitness domain.
Working out by yourself is fine if you’re self-motivated, but getting a buddy to tag along can provide the motivation needed to really ramp up your workout. Let’s face it—a bit of friendly competition can help you push harder than if you were alone. In fact, research has consistently shown that performance is substantially improved when you exercise with someone (even a virtual partner)—unless the workout is complex or involves tasks that require coordination, when the performance can degrade (i.e., "choking under pressure"). So, for best results, practice your difficult routines with a trainer, and then engage in healthy competition to optimize your performance. Keep in mind that not just any friend will do. It’s best to get a buddy whose skill level is similar to your own.
If you have ever bought a pair of toning shoes, you probably noticed you haven’t developed a Kardashian-curved derrière or a Brook Burke body just from walking around in them. You’re not alone. Recent developments have brought toning shoes back into the spotlight for the media and scientific communities. An independent study by the American Council on Exercise found that these kinds of toning shoes do not increase muscle activation or caloric expenditure compared to regular athletic shoes. However, a positive outcome may be that these shoes have motivated people to get out and walk, a physical activity that has many health benefits—without special shoes! Caveat emptor!
A recent article in the New York Times looks at the combination of neuroscience and exercise. A new theory suggests that your brain, not your hormones, increases or decreases your appetite after a workout. Researchers at California Polytechnic State University studied different areas of the brain that control whether we want and like food and how these areas are affected by exercise or sitting still.
Scientists found that “responsiveness to food cues was significantly reduced after exercise.” Compared to sitting for an hour, exercisers were much less interested in food, even ice cream sundaes. The subjects in the study were in their 20s and fit enough to sustain strenuous exercise for an hour. This is in contrast to a study that found the same areas in the brain were excited in an overweight and sedentary population after exercise, causing them to want and eat more food.
While the effect is still unclear and more variables need to be tested, researchers conclude that exercise has a definite impact on how your brain responds to food.
In a recent study investigating risk factors for discharge from Army Basic Combat Training (BCT), researchers concluded that increased risk for both men and women was associated with failure on the initial two-mile run test. The current Physical Fitness Tests (PFT) or Physical Readiness Test (PRT) use a one and a half to two-mile run test to assess cardiovascular, or aerobic, fitness.
When mapping out a fitness program, learn the components of the FITT principle and apply them for each type of training. FITT stands for “frequency,” or how often; “intensity,” or how hard; “type,” or the kind of activity; and “time,” or how long. Progression (see below) is also an important part of an exercise plan. Using the FITT Principle, here are some guidelines to help optimize your cardiovascular fitness.
Frequency. The U.S. Surgeon General and other U.S. government agencies recommend physical activity on three or more days a week.
Intensity. According to updated guidelines The American College of Sports Medicine (ACSM) recommends adults engage in moderate-intensity exercise (i.e., at 40-60% Heart Rate Reserve (HRR)) five days a week or vigorous-intensity exercise training (i.e., at ≥ 60% HRR) three or more days a week. They also recommend a combination of moderate- and vigorous-intensity exercise. You can use this calculator from Kirtland AFB to determine your HRR.
Type. ACSM defines aerobic activities as being continuous, rhythmic, and using large muscle groups, such as your lower and upper body muscles. Examples of these kinds of activities are running, biking, swimming, rowing, and jump roping.
Time. The Surgeon General, ACSM, and American Heart Association recommend expending at least 1,000 calories per week through exercise (i.e., in addition to calories burned through normal everyday activities). This can be achieved through moderate-intensity exercise, as described above, and should last about ≥ 30 minutes per day for a total of ≥ 150 minutes per week; or with vigorous-intensity exercise for ≥20 minutes per day for a total of ≥75 minutes per week. The maximum safe duration is unknown, but exercise lasting more than an hour and a half increases risk of overtraining and/or overuse injuries such as stress fractures.
Progression. During the initial phase of an exercise program, ACSM recommends increasing duration (minutes per session) gradually. Increasing 5-10 minutes every one or two weeks over the first four to six weeks of an exercise program is reasonable for healthy adults. After an exercise routine has been maintained for one month or longer, it is reasonable to gradually increase frequency, intensity, and/or time over the next four to eight months. As a general rule of thumb, though not scientifically backed, increasing your workloads or volume by 10% will also help you gradually progress your exercise program.
Due to the repetitive and rhythmic nature of aerobic exercise, overuse injuries can occur as a result of your training. Cross training—training with a variety of aerobic exercises—is recommended. Examples of this would be alternating running, swimming, and rowing exercise sessions.
Part two of this series (upcoming) will address the muscular strength component of PFT/PRT.
There are several risk factors for stress fracture development, but a 2011 article in Medicine and Science in Sports and Exercise found that maintaining adequate muscle strength and flexibility in the hips, legs, knees, ankles, and feet is of great importance, especially for women. Here are some exercises from the American Council on Exercise that can help you build strength and flexibility:
Before beginning any exercise program, however, make sure to consult with a medical professional, especially if you are more than 45 years old.
National Nutrition Month is still going strong, bringing lots of healthy eating information to the attention of Americans. The Academy of Nutrition and Dietetics is weighing in with their “Get Your Plate in Shape” campaign, which focuses on getting the right nutrition without too many calories. Their Eat Right website page offers snack ideas, recipes, weight management tips, and exercise nutrition advice.
Kettlebells have been used in Europe for years in strength training, and now they’ve become a popular workout tool here in the United States too. The benefit of kettlebells is that they provide the user a wider range of motion than dumbbells do. Kettlebell workouts engage multiple muscle groups at once, making them a great option for getting a whole-body workout in a short time.
Interestingly, the January 26 edition of the New York Times Health Section reported on a Danish study that suggests kettlebell exercises are a promising musculoskeletal therapy for low-grade back and neck pain.
The study involved middle-aged women with low-grade back, shoulder, and neck pain who were randomly assigned to either a regular kettlebell workout or a general-exercise control group. The study did not include those with chronic pain.
According to the Times article, at the end of the study, the group that did the kettlebell exercises reported less pain, as well as improved strength in the trunk and core muscles, compared with the control group. Overall, the study showed exercising with kettlebells reduced lower-back pain by 57% and neck and shoulder pain by 46%.
For those with core-muscle instability or weak core muscles, kettlebells can be a great way to strengthen those muscles (back, abdominal, glutes, quads, hamstrings) and improve posture. However, along with exercise it is imperative to stretch the hamstrings, since this tends to be a major contributor to lower back pain or discomfort.
It’s important to start slow when using kettlebells and seek professional guidance. Like any other exercise equipment, if used improperly, kettlebells can cause serious injury, and their swinging motion can be difficult to control.