New exercise guidelines

In 1995 the American College of Sports Medicine (ACSM) and the Centers for Disease Control and Prevention (CDC) published national guidelines on Physical Activity and Public Health that led to our current 30 minutes a day of gentle exercise guidelines.
This month has seen these guidelines revised, in line with more up to date research.

In this article we take a look at the new guidelines and assess where they leave the general population today.

The old guidelines seemed to give most people a false sense of what is necessary to achieve and maintain fitness and overall health. They were also extremely vague, with Mr, Miss & Mrs Average being left to work out and implement vital health and fitness issues such as ‘how much exercise is optimal for me?’ and ‘what intensity should I exercise at?’ on their own.

Not only did the previous guidelines give a false comfort level but they also failed to provide sufficient information to allow that level to be implemented in any effective way.

So we ended up with this result: sadly less than half (49.1%) of U.S. adults met the CDC/ACSM physical activity recommendation with 23.7% of adults reporting no leisure-time activity at all. (1) Saying: “do something for 30 minutes a day” was a step in the right direction, a shift towards more specifics was badly needed.

Although it took a monumental 12 years to address this fundamental issue, new guidelines were released in August 2007 to international media coverage.

Let’s look at the updated recommendations in more detail before we assess where they leave us. They suggest (1):

Moderate intensity aerobic physical activity (briskly walking) for a minimum of 30 min (authors note: is there a maximum?) on five days each week or vigorous intensity aerobic physical activity (jogging) for a minimum of 20 min on three days each week.
Combinations of moderate and vigorous intensity activity can be performed to meet this recommendation. For example, a person can meet the recommendation by walking briskly for 30 min twice during the week and then jogging for 20 min on two other days.
In addition, every adult should perform activities that maintain or increase muscular strength and endurance a minimum of two days each week. This means activities - such as weight lifting - that use the major muscles of the body. You should do eight to ten exercises on two different days at least one day apart.
Persons who wish to further improve their personal fitness, reduce their risk for chronic diseases and disabilities or prevent unhealthy weight gain may benefit by exceeding the minimum recommended amounts of physical activity (Authors note: by how much?)



It cannot be understated that this is a real step in the right direction and is to be applauded, but one does find oneself asking the question: How far do the new guidelines really take us towards a healthier society and where could they be strengthened to allow a deeper understanding of what is required to make us fitter and healthier human beings?

As a health and fitness professional working day to day on the ground I’d like to take a moment to outline three major improvements that I think are easy to communicate and easy to implement:

1. The recent guidelines state that aerobic activity for 30 mins (gentle) or 20 mins (vigorous) should be minimums – does that mean ‘more is better?’ and if so how far should we go in using aerobic exercise?

The issue is that excessive aerobic activity can lead to a decrease in muscle mass due to muscle potentially being used as a fuel, and from the production of catabolic hormones that break the active tissue down.

I am by no means suggesting that aerobic/cardio activity is bad. Indeed it is vital, as it allows nutrients to be transported to the cells via the bloodstream. When fat is released from storage centers (adipose cells) it travels through the bloodstream to be ‘burned’ and this is facilitated by cardio activity, but a decrease in muscle mass due to excesses in this form of exercise leads to a decrease in the body’s ability to burn fat.

Hence the most beneficial method of performing your cardiovascular component of exercise is through interval training methods, focusing on shorter periods (10-20 minutes) at med/high intensities with breaks in between. It is to be noted that what medium/high intensity means is relative to each person’s baseline level of fitness. In addition I would recommend performing aerobic/cardiovascular sessions no longer than 40 minutes in duration to avoid muscle mass loss and the associated issues mentioned above.

Through providing clearer and more specific guidelines optimum and more effective levels of exercise are possible without lessening the general population’s ability to implement the exercise regime.

2. Effective resistance training is the key to any program aimed at achieving weight loss, so its inclusion in the new guidelines is a major plus.

Focusing on resistance training will lead to fitter, leaner and stronger bodies as when we reach around age 30 our muscles begin to shrink, leading to a metabolic rate decrease and therefore a decreased ability to burn fat. (2) The guidelines however, do not take into account the need to change the variables in such resistance training.

The suggestion that, “a resistance (weight) should be used that results in substantial fatigue after 8-12 repetitions of each exercise” is severely limiting. I often see people in the gym still doing their ‘3 sets of 10’ with no additional results after one month’s training. It’s easy to get to ‘first base’ doing things this way, but getting any further results is unlikely.

In addition many would suggest that recommending weight training is an unrealistic edition and ‘not for the majority’. I believe this is where more education on the benefits (like increased fat-loss and strength) needs to be highlighted.

I recently read one expert called David Haslam, chair of the U.K. National Obesity Forum, commenting that: "If you suggested everyone here should do weight-training twice a week they wouldn't do it. They don't have the time or money for the gym, it would be an unrealistic guideline. I'd rather see healthy habits built into daily life - gyms aren't a sustainable habit." (3)

This is a very limited perspective from which to view the possibilities of effective resistance training. Resistance training does not need a gym membership, just a little creativity will do and it can be easily and cheaply done at home with:

· Uncomplicated body weight exercises like pushups, squats, lunges, chin ups that require no equipment and little space.
· Simple inexpensive equipment like: bands, tubing, medicine balls, stability balls, dumbells, with perhaps a small investment in one of the many home training books, dvd’s, or online programs out there.

To achieve consistent changes in strength and body composition programs must be changed regularly every 2-4 weeks, including the number of repetitions, sets, exercises, rest periods and intensity, and made progressive (i.e. harder each session).

This kind of guidance would be a major addition to the recent guidelines.

3. There is no mention of flexibility training which simply must be mentioned under any exercise guidelines.

We are currently experiencing an epidemic of pain and overuse injuries such as Repetitive Strain Injuries (RSI’s). According to the U.S. Department of Labor, Occupational Safety and Health Administration (OSHA), RSI’s are the nation’s most common and costly occupational health problem, affecting hundreds of thousands of American workers, and costing more than $20 billion a year in workers compensation. They account for 14% of physician visits and 19% of hospital stays. (4)

Through effective stretching this could be reduced and the general health of the nation would be improved too!

The new exercise guidelines are a definite improvement on those released in 1995 but in much the same way that grains are still being used as the basis of the food pyramid at a time of growing public awareness that grains may be a barrier to health. The recommendation that emphasizes longer duration cardiovascular exercise over resistance training is a flaw that will keep people back from achieving permanent weight loss.

The fact is that despite the recent guidelines the bar is still too low and ill defined to bring real benefit to the general population.



References

(1) Physical Activity and Public Health: Updated Recommendation for Adults from the American College of Sports Medicine and the American Heart Association. Medicine & Science in Sports & Exercise: Volume 39(8)August 2007pp 1423-1434 http://www.acsm-msse.org/pt/re/msse/fulltext.00005768-20070800000027.htm;jsessionid=GMwPjzCJtwyTZyJLmx1ndlQMP1pK6TLBjdVKqqPnM1Z2LGTvg14S!-362743511!181195628!8091!-1

(2) 3dpts.com: Strong beginnings – success through synergy. Craig Burton http://www.3dpts.com/ArchiveArticles/BodyArticle/2005-10-Bodyarticle.htm

(3) The Guardian: The era of gentle exercise is over. Its official: you've got to work up a sweat. Polly Curtis, health correspondent, Friday August 17, 2007 http://lifeandhealth.guardian.co.uk/health/story/0,,2150618,00.html

(4) RSI Therapy.com: RSI Stastics. http://www.rsi-therapy.com/statistics.htm