Walking Improves Brain Health

Walking approximately 6–9 miles a week is associated with increased gray matter in the brains of older adults, according to a study published in Neurology (2010; 75 [16], 1415–22) “Just by walking regularly, and so maintaining a little bit of moderate physical activity, you can reduce your likelihood of developing Alzheimer’s disease and [can] spare brain tissue,” Kirk I. Erickson, lead study author and assistant professor of psychology at University of Pittsburgh [Pitt] in Pennsylvania, told HealthDay. The study participants were subjects in the Pittsburgh site of the larger Cardiovascular Health Cognition Study, a longitudinal study conducted over a 13-year period. 

The Pitt researchers wanted to determine whether consistent moderate physical activity among older adults would be associated with cognitive health in later life. The scientists enrolled 299 adults with a mean age of 78 in 1989 and recorded the distance each person walked per week. Nine years after this measurement, investigators conducted MRI brain scans to measure brain size. At this stage, none of the participants exhibited any cognitive impairment. Four years later, approximately one-third of the subjects had experienced cognitive decline. 

Data analysis showed that the individuals who walked a minimum of 6 miles per week had more gray-matter volume in the brain and only half the risk of developing cognitive impairment compared with less active subjects. Sections of the brain that retained more gray matter included the frontal and temporal brain regions, including the hippocampus and the entorhinal cortex. These brain regions can be subject to age-related deterioration. More gray matter in these areas is associated with reduced risk of developing dementia or mild cognitive impairment. 

More physical activity, however, does not provide more benefits. “That’s because the size of our brain regions can only be so large,” said Erickson. However, the improvements that can occur are important: “What we often think of as an inevitable component or characteristic of aging—memory decline and brain decay—is clearly not inevitable. There’s plenty of evidence now . . . that shows that we can retain our brain tissue and retain our memories well into late adulthood by maintaining an active and engaged lifestyle.”

By Shirley Archer, IDEA Fit

Anaerobic Training Programs: Program Design

 

 

Most personal trainers design anaerobic workouts for their clients—it is an innovative strategy that helps many people reach their goals. Competitive athletes have been training anaerobically for years. But these types of programs also offer recreational exercise enthusiasts challenge, variety and unique physiological adaptations.

This article provides an overview of the scientific theory and physiology underlying the bioenergetic systems emphasized in anaerobic conditioning and introduces program design guidelines and ideas.

Anaerobic Training Programs: Program Design

Remarkably, little research has been published to summarize the best training methods for anaerobic fitness. Researchers, coaches and exercise professionals have consistently targeted specific muscles or movement patterns for athletic races or events and have designed progressively increasing training strategies (i.e., using the overload principle). Fortunately, one of the most comprehensive, practical, evidence-based articles on anaerobic metabolic conditioning—by Plisk (1991)—provides splendid guidance and theory-driven direction for overall anaerobic program design. Plisk focuses on the following key areas: repetition intensity/duration, exercise-to-relief ratio, total exercise volume, training frequency, program duration, value of resistance training design, and training progression.

Repetition intensity/duration. Exercise intensity is considered a primary stimulus for anaerobic conditioning. Plisk notes that the phosphagen energy system and glycolytic-glycogenolytic pathways are best trained with exercises that increase intensity or speed (without compromising technique) rather than with longer-duration exercises. These energy systems dominate the first 120 seconds of exercise. Personal trainers use heart rate monitoring as a relative intensity guideline for how hard acardiovascular exercise is being performed. With anaerobic conditioning, however, heart rate measurement is a poor indicator of exercise intensity, as neurological factors elevate heart rate disproportionately during anaerobic exercise. Exercises are often performed over a continuum of somewhat hard, near-maximal and maximal intensities. Plisk suggests that trainers focus on exercise quality (not quantity) and sufficient intensity for eliciting optimal training responses and adaptations.

Exercise-to-relief ratio. Bishop, Girard & Mendez-Villanueva (2011) assert that with repeated exercise bouts (e.g., sprints), phosphocreatine restoration (or resynthesis) is of great concern because it is the most rapid supplier of ATP for the contracting muscle proteins during anaerobic training. The authors affirm that complete phosphocreatine resynthesis takes up to 3 minutes after high-intensity exercise. For repeated bouts, Plisk suggests using a 1-to-4 exercise-to-relief ratio initially and then, over a period of weeks, tapering to a 1-to-2 or 1-to-1.5 ratio. Therefore, if an exercise takes 30 seconds to complete, initially the 1-to-4 exercise-to-relief ratio indicates that the client should recover for at least 120 seconds and then repeat the exercise. Athletes may perform multiple sets of exercise-to-relief bouts. For this strategy, Plisk recommends allowing a minimum of 2 minutes between sets for near-complete phosphagen resynthesis.

Interestingly, Bishop, Girard & Mendez-Villanueva note that an active recovery, such as walking or jogging, is optimal for enhancing phosphocreatine resynthesis and for clearing the buildup of hydrogen ions (from the splitting of ATP). The same authors explain that persons with higher aerobic fitness levels are able to resynthesize phosphocreatine more effectively, thus emphasizing a unique benefit of cardiovascular exercise (for improving anaerobic performance).

Training frequency. Anaerobic training frequency for athletes may be quite different from what is appropriate for recreational clients. In view of previously established parameters to train for quality and not quantity, Plisk suggests that trained individuals take 2–3 rest days per week. This should provide sufficient recovery between workouts while preventing overtraining.

Program duration. Consistent anaerobic conditioning has been shown to meaningfully improve several physiological components—including oxidative capacity, phosphocreatine recovery, hydrogen ion buffering, and muscle activation and recruitment—in as little as 5 weeks (Bishop, Girard & Mendez-Villanueva 2011). This information can be useful to personal trainers wishing to educate clients about how long it will take to start realizing changes from anaerobic training.

Value of resistance training. Some clients want to improve anaerobic performance in recreational activities such as short races. Research indicates that maximal strength improvement is less favorable with resistance training programs. Resistance training that includes a high metabolic load—such as sets of 10- to 20-repetitions maximum (i.e., a person can complete 20 repetitions but not 21)—have proved optimal (Bishop, Girard & Mendez-Villanueva 2011). Plisk points out that many sprint-type and explosive competition sports involve a lot of ballistic, stretch-shortening, eccentric contractions; he therefore recommends resistance training involving controlled eccentric contractions. Personal trainers may wish to incorporate a 1-second concentric phase with a 4-second eccentric phase for many of the target exercises and movements they select.

by Len Kravitz, PhD, Nick Beltz, MS, Jonathan N. Mike, MS