Interval Training as Effective as Endurance Training

Interval training.

A study at McMaster University in Ontario has investigated whether sprint interval training (SIT) is a time-efficient exercise strategy to improve insulin sensitivity and other indices of cardiometabolic health to the same extent as traditional moderate-intensity continuous training (MICT). SIT involved 1 minute of intense exercise within a 10-minute time commitment, whereas MICT involved 50 minutes of continuous exercise per session.

Twenty-seven sedentary men, mean age 27, were each assigned to one of three groups: three sessions of either SIT or MICT per week for 12 weeks; non-training controls. SIT involved 3×20 second ‘all-out’ cycle sprints (~500W) interspersed with 2 minutes of cycling at 50W, whereas MICT involved 45 minutes of continuous cycling at ~70% maximal heart rate (~110W). Both protocols involved a 2-minute warm-up and 3-minute cool-down at 50W.

Indices of cardiometabolic health, such as peak oxygen uptake and glucose sensitivity, increased equally in both groups, despite sprint interval training requiring a five-fold lower exercise volume and time commitment.

The authors point out that most studies of high intensity training have lasted only a few weeks to several months, and have involved small numbers of subjects. Much of this work has examined physiological changes in young healthy individuals. Only a handful of studies have looked at non-healthy individuals including those with cardiometabolic diseases such as type-2 diabetes. While generally found to be safe, perceived as enjoyable and well-tolerated in laboratory studies, only a few studies have examined the feasibility of implementing the training in normal life, where people have to undertake it on their own. It also remains unknown whether adherence to this form of training is any better than for continuous moderate-intensity exercise.

(Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training despite a Five-Fold Lower Exercise Volume and Time Commitment. PLOS, 26 April 2016.)

Acupuncture helps Post-Exercise Fatigue

Acupuncture fatigue: The Exeter Great West Run
A pilot study has shown that acupuncture can speed the relief of post-exercise fatigue, by re-regulating energy metabolism and reducing the effects of oxidative stress. Fourteen young male athletes were given a standard dietary plan for two days, and then undertook a series of exhaustive running exercises followed by a short rest. They were then either given a 30 minute acupuncture treatment, or were allowed to simply rest for a further 35 minutes. NMR-based metabolomics analysis was used to assess the metabolic profiles of urine samples collected from all the athletes before exercise, before & after acupuncture, and while taking the extended rest period.

The results indicated that levels of key metabolites which had been disturbed by exercise, recovered significantly faster in the athletes given acupuncture, compared with those who simply rested. In addition, markers related to choline metabolism and oxidative stress caused by the generation of reactive oxygen species, recovered faster in the acupuncture group. The authors say this work begins to unravel biochemical mechanisms behind the effect of acupuncture on recovery, and they speculate on its usefulness in sport.

(The Intervention Effects of Acupuncture on Fatigue Induced by Exhaustive Physical Exercises: A Metabolomics Investigation. Evidence Based Complementary & Alternative Medicine, 2015.)

Skipping Breakfast Impairs Sports Performance Later in Day

Breakfast and sports performance: Eating breakfast can help you perform better.
Elsewhere on my website, you will see my strong encouragement to eat breakfast. Now, besides the other benefits, researchers at Loughborough University have found that skipping breakfast can impair sports performance much later in the day.

Ten male, habitual breakfast eaters were put through two different trials. All participants arrived at the laboratory having fasted overnight, but they then either consumed or omitted a 733kcal breakfast. Subjects were allowed to eat freely their lunch 4.5 hours later and dinner 11 hours later. At the 9 hour point, they were put through an evening exercise test, completing a 30 minute cycling test at around 60% VO2 peak followed by a 30 minute maximal cycling performance test.

Perhaps not surprisingly, those who had not eaten breakfast, consumed around 200kcal more at lunch, but those who did eat breakfast, interestingly consumed more at dinner. The novel finding is that those who consumed breakfast, performed a significant 4.5% better during the exercise performance test.

(Effect of Breakfast Omission on Energy Intake and Evening Exercise Performance. Medicine & Science in Sports & Exercise, online 12 May 2015. See

Vitamin C and E Supplements may hamper Endurance Training

Too much of vitamins C and E supplements may interfere with endurance training.

Researchers at the Norwegian School of Sport Sciences, have found that taking vitamin C and E supplements may interfere with endurance training. High doses of vitamins C and E act as antioxidants, which is why athletes are attracted to them, but removing this oxidative stress, may block muscular endurance development.

In an eleven week, double-blind trial, 54 healthy young men and women were randomly allocated to receive either 1000mg vitamin C plus 235mg vitamin E, or a placebo pill containing no active ingredients. The participants then undertook an endurance training programme, consisting of three to four sessions per week, primarily of running. Fitness tests, blood samples and muscle biopsies were taken before and after the programme.

In endurance training, an adaptation is normally observed in the exercised muscles; this adaptation is characterised by an increase in mitochondrial proteins to improve muscular endurance. The results of this trial however, showed that in the group taking the vitamins, this increase was blunted.

Dr Gøran Paulsen, who led the study, says,“Our results indicate that high dosages of vitamin C and E – as commonly found in supplements – should be used with caution, especially if you are undertaking endurance training. Future studies are needed to determine the underlying mechanisms of these results, but we assume that the vitamins interfered with cellular signalling.

(Journal of Physiology, on-line 3 February 2014.)

Robin’s note: If you wish to address free radical generation during exercise, then instead try using food to do it. You need food with a high ORAC (oxygen radical absorption capacity) rating. Prunes are top of the list, followed by things like raisins, blueberries, blackberries, strawberries, kale and spinach.

Acupuncture superior to Exercise for Achilles Inflammation

Acupuncture for Achilles inflammation.
Researchers have found that compared with exercise therapy, acupuncture can produce significant and more rapid improvements in pain and activity levels in patients with chronic Achilles tendinopathy. Sufferers usually have pain, swelling and stiffness, often induced by overuse eg running, and treatment includes rest, painkillers and exercises to stretch and strengthen the tendon. The road to recovery can take three to six months.

In a randomized, controlled trial, 64 patients aged 18 to 70, were allocated to receive either acupuncture or exercise therapy. After 16 weeks, acupuncture had produced a symptom improvement of 26 points on a 100 point scale, compared with only 10 points for exercise therapy. After 24 weeks, these figures were 28 points and 17 points respectively. The researchers conclude acupuncture intervention could improve pain and activity in patients with chronic Achilles tendinopathy, compared with eccentric exercises.

(Acupuncture for Chronic Achilles Tendinopathy: A Randomized Controlled Study. Chinese Journal of Integrative Medicine, on-line 21 December 2012)