Diet is only half the diet-and-exercise prescription for good health.
Eating patterns that limit calorie intake and favor whole foods – including fish – can help maintain healthful weight and overall wellness.
But we also need regular exercise to reduce disease risk, maintain healthy metabolism and weight, and just plain feed good.
It's ideal to exercise both ways, regularly (see our sidebar, "What are the best interval options?"):
- Aerobic (running, cycling, swimming)
- Resistance (pull-ups, pushups, sit-ups, crunches, bands, and free or machine weights).
Aerobic exercise is the most critical kind for metabolic health and weight control, though resistance helps a lot.
Truth is, many people find it hard to maintain an aerobic exercise routine … in part because they don't see or feel progressive, emotionally rewarding gains in performance and ease.
What are the best interval options?
Whether you do them outdoors or inside, the pros and cons of the basic options remain the same:
- Cycling is good if you have knee or foot problems or just don't like running.
- Running (on ground or a treadmill) works more muscles with more variations and also beats cycling for delivering the shocks critical to promoting bone growth.
- Swimming works upper body and core muscles more than either biking or running do and is good if you have knee or foot problems.
Alternating exercise intensity gains ground over steady as you go
Research published over the past decade or so finds startling benefits from alternating high-intensity and low-intensity exercise … in rather short sessions.
In this kind of interval training – called high-intensity interval training or HIIT – people typically do 10 minutes of intense exercise in each 30 minute exercise session, including a brief warm-up, short between-intervals “recovery” periods, and a final low-intensity cool down.
One common 30-minute HIIT routine is to alternate sprinting (about 10 minutes total) with brisk, unforced walking (about 20 minutes total).
The idea is to run (or cycle or swim) vigorously for as long as your lungs and muscles will allow, then go slow until you feel ready to “sprint” again.
Most people find that this almost automatically results in spending about one-third of their session doing high-intensity exercise.
There's now ample evidence that HIIT yields metabolic improvements as good or better than those achievable by much longer periods of moderate “endurance” training … such as longer-distance running or cycling.
Last month, researchers at Canada's McMaster University conducted a review of the evidence on so-called high-intensity interval training or HIIT, in order to quantify its benefits versus endurance training.
The Canadians concluded that – compared with longer time spent in steady moderate exercise – three HIIT sessions per week improve aerobic capacity, muscle metabolism, exercise tolerance, and markers of disease risk.
These benefits appear within a few weeks of stating HIIT, both in healthy people and those cardiovascular disease, diabetes, or other cardio-metabolic disorders.
For example, a recent trial from Scotland suggests that HIIT is more rewarding – and more motivating – compared with longer periods of moderate-intensity aerobic exercise.
Scottish trial crowns interval training
Scientists from Scotland set out to see whether moderate or high-intensity cycling delivered the fastest, best results.
They say their findings reveal a secret to making exercise shorter and more rewarding … and more likely to keep people exercising (Neal CM et al. 2013).
“Quantity and quality of training has provided a quandary for coaches and athletes for many years, but this study is the first of its kind to provide an answer to the problem,” said Dr. Stuart Galloway, who led the study (US 2013).
Exercise scientists from Scotland's University for Sporting Excellence put 12 cyclists through their paces over a 29-week trial period.
They split the cyclists into two groups of six each and put them through different exercise session:
- HIIT (high-intensity interval training) – 80 percent low and 20 percent high intensity
- MIIT (moderate-intensity training – 55 percent low and 45 percent moderate intensity. After a four week rest period, the groups switched over to other group's exercise pattern.
The results showed that the HIIT sessions boosted cyclists' power and performance twice as much as the session of low and moderate intensity training.
This combination also enhanced muscle recovery after exercise … a vital component in improving physical health. Dr. Angus Hunter, a co-author on the study, put it this way (US 2013):
“Your muscles may be fatigued more quickly when you work at a high intensity, but they recover more quickly too. Our study suggests that a much quicker recovery occurs when adopting the low and high intensity combination.”
As Dr. Galloway said, “It's a case of training smarter. We found that if you can make the hard sessions harder and the easy sessions easier then you will likely see better progress.” (US 2013)
And he made a key point: “Amateur athletes tend to spend a lot of their training in a moderate intensity bracket which in our study showed much smaller improvements.” (US 2013)
People have been advised – perhaps misguidedly, it now seems – to do moderate-level intensity exercise for about three hours a week.
Fortunately, this new trial and other recent studies show that we can gain more benefits – in less time – by alternating high- and low-intensity exercise.
Burgomaster KA, Howarth KR, Phillips SM, Rakobowchuk M, Macdonald MJ, McGee SL, Gibala MJ. Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. J Physiol. 2008 Jan 1;586(1):151-60. Epub 2007 Nov 8.
Creer AR, Ricard MD, Conlee RK, Hoyt GL, Parcell AC. Neural, metabolic, and performance adaptations to four weeks of high intensity sprint-interval training in trained cyclists. Int J Sports Med. 2004 Feb;25(2):92-8.
Gunnarsson TP, Christensen PM, Thomassen M, Nielsen LR, Bangsbo J. Effect of intensified training on muscle ion kinetics, fatigue development, and repeated short-term performance in endurance-trained cyclists. Am J Physiol Regul Integr Comp Physiol. 2013 Oct 1;305(7):R811-21. doi: 10.1152/ajpregu.00467.2012. Epub 2013 Jul 24.
Hood MS, Little JP, Tarnopolsky MA, Myslik F, Gibala MJ. Low-volume interval training improves muscle oxidative capacity in sedentary adults. Med Sci Sports Exerc. 2011 Oct;43(10):1849-56. doi: 10.1249/MSS.0b013e3182199834.
Iaia FM, Hellsten Y, Nielsen JJ, Fernström M, Sahlin K, Bangsbo J. Four weeks of speed endurance training reduces energy expenditure during exercise and maintains muscle oxidative capacity despite a reduction in training volume. J Appl Physiol (1985). 2009 Jan;106(1):73-80. doi: 10.1152/japplphysiol.90676.2008. Epub 2008 Oct 9.
Laursen PB, Jenkins DG. The scientific basis for high-intensity interval training: optimising training programmes and maximising performance in highly trained endurance athletes. Sports Med. 2002;32(1):53-73. Review.
Laursen PB, Shing CM, Peake JM, Coombes JS, Jenkins DG. Influence of high-intensity interval training on adaptations in well-trained cyclists. J Strength Cond Res. 2005 Aug;19(3):527-33.
Little JP, Safdar A, Wilkin GP, Tarnopolsky MA, Gibala MJ. A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms. J Physiol. 2010 Mar 15;588(Pt 6):1011-22. doi: 10.1113/jphysiol.2009.181743. Epub 2010 Jan 25.
Logan GR, Harris N, Duncan S, Schofield G. A Review of Adolescent High-Intensity Interval Training. Sports Med. 2014 Apr 18. [Epub ahead of print]
Neal CM, Hunter AM, Brennan L, O'Sullivan A, Hamilton DL, De Vito G, Galloway SD. Six weeks of a polarized training-intensity distribution leads to greater physiological and performance adaptations than a threshold model in trained cyclists. 2013 Feb 15;114(4):461-71. doi: 10.1152/japplphysiol.00652.2012. Epub 2012 Dec 20. Erratum in: J Appl Physiol. 2013 May 15;114(10):1490. http://jap.physiology.org/content/early/2012/12/18/japplphysiol.00652.2012.abstract
University of Stirling (US). Breakthrough reveals secret to successful exercise programmes. January 17, 2013. Accessed at http://www.stir.ac.uk/news/news-archive/13/01/sports-science-study/name-37509-en.html