Filed under: Exercise
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.
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.
At the U.S. Army Garrison in Kaiserslautern (Germany), the base is trying to find more ways to include families in physical fitness. They are providing classes— called “Binkies and Babes” —that spouses can do with their babies. These classes are great ways for spouses to workout with their young children, socialize with other military families, and get a great individual workout!
Overseas military families can sometimes find it difficult to both exercise and manage child care. This is one way overseas bases are moving towards Total Family Fitness. Renee Champagne, the Fitness Coordinator for the Army bases in Germany (and a military spouse herself), sees how “working out and staying physically fit may help a spouse cope during a deployment… which in turn could provide peace of mind to the military member downrange.”
For more information, see the article and video on Stars and Stripes.
There’s a phenomenon runners sometimes experience that’s commonly called “runners’ trots” – otherwise known as diarrhea – that has risk factors and that can possibly be avoided. Although the “trots” usually don’t last long and are generally nothing to worry about, they certainly can be a major annoyance, causing lost time in training or competition and even embarrassment if there is literally “nowhere to go.”
The most common risk factors cited are for those who are young, female, susceptible to irritable bowel syndrome, or lactose intolerant, as well as those who have had a previous abdominal surgery. The things we do to our bodies that reportedly increase risk are high-intensity exercise, dehydration, vertical-impact sports (e.g., running vs. biking), poor conditioning, medication, and diet. Although these are stated in the medical literature as risk factors, a recent study published in the International Sportmed Journal examined the evidence behind each of these risks to see if they hold up under scrutiny – and there’s surprisingly little evidence to support many of the statements about risk factors for developing “runners’ trots.” Most of the evidence was limited and relied on either single studies or multiple studies with varying results but a tendency toward supporting the conclusion.
Here are the conclusions of this evidence-based study:
The only strongly supported evidence was for dehydration to increase the risk of diarrhea. Female gender, younger age, high-intensity training, vertical impact, and medication had limited support and could go either way. Finally irritable bowel, lactose intolerance, previous abdominal surgery, poor conditioning, and dietary factors had very weak support. Keep in mind that little or no evidence does not make something true or false; it just means we have insufficient scientific evidence for any assumption.
So, based on the studies, how can you avoid “runners’ trots?”
- The evidence certainly supports staying well hydrated so that the bowel gets an adequate blood supply.
Even though the evidence for doing some things is not strong, they make sense and are not harmful. These include:
- Avoid a large meal 3-6 hours prior to running.
- Avoid food or drinks that have non-absorbable sweeteners (such as sorbital or sucralose), caffeine, and/or a high fat content.
- Don’t ingest concentrated carbohydrates (high glycemic index) before running.
- Be aware that energy bars and gels may contribute to the “trots” for some people.
- Avoid taking anti-diarrheal medications such as loperamide (e.g., Imodium) or Lomotil, since they can affect the ability of the body to tolerate heat.
- Wear loose-fitting clothing to reduce irritation.
- If symptoms persist for more than a few days, seek medical attention to be sure there is not an underlying cause.
Enjoy your run!
Warfighters have specific physical activity requirements, but their spouses, children, parents, and other loved ones also have physical fitness requirements for their own individual and family missions. HPRC's family section has a new area that summarizes recent guidelines for physical activity for U.S. adults, and children, and identifies military resources, interactive tools, and exercise workouts and videos. Check it out here!
Running is a great exercise to help reduce your risk of heart disease and stroke. Running improves your cardiovascular system by strengthening your heart muscle and improving your circulation. As your heart muscle becomes stronger, your heart can pump more blood more easily. This helps deliver more oxygen to fuel your working muscles and remove byproducts such as carbon dioxide.
With the holiday season upon us, finding time for our usual workouts can sometimes be difficult. Two great physical fitness resources are the American College of Sports Medicine (ACSM) and the American Council on Exercise (ACE). Each has online workouts that you can try for free.
For a total body workout that you can do at home with free weights, try this total body workout from ACE that includes videos of the warm-up, the workout, and the cool-down. For a total body workout without additional equipment, try this at-home workout.
If you have less time, try this Basic Bodyweight Strength Training Program from ACSM.
Fit in these workouts in at home through the holiday season to keep you on track.
Brazilian Jiu-Jitsu—or BJJ—focuses on ground fighting techniques, also known as grappling. You can start your training at a level appropriate to your physical fitness, but ultimately you will find that your endurance increases as your opponent also learns the techniques designed to dominate. Although BJJ requires little to no physical strength—mainly technique and balance—you will find that your muscle tone and mass increase gradually without requiring weight training.