Research Quarterly for Exercise and Sport, November 2014
Here's something for all of the 10 miles/day people who suffer from "chronic cardio" disease. A recent study out of British Colombia has found that high intensity interval training may be an effective tool for improving postprandial hyperglycemia (the rise in blood sugar following a meal) in individuals with, or at risk for type 2 diabetes. HIIT is defined as, "repeated vigorous-intensity efforts lasting from a few seconds up to several minutes, separated by short periods of rest or recovery" (Little & Francois, 2014, p. 452). When compared to traditional "steady-state," continuous moderate-intensity exercise, HIIT has been shown to offer a more favorable exercise stimulus for improving postprandial hyperglycemia by: (a) promoting a higher degree of muscle fiber recruitment (Edgett et al., 2013), (b) causing greater depletion of muscle glycogen (Shiose, Tobina, Higaki, Kiyonaga, & Tanaka, 2012), (c) promoting a greater activation of 5’ adenosine monophosphate-activated protein kinase (Chen et al., 2003), and/or (d) promoting an increase in skeletal muscle glucose transporter 4 (Hood, Little, Tarnopolsky, Myslik, & Gibala, 2011; Little et al., 2011). In addition to the scientific jargon, other potential long-term benefits of HIIT include: better body composition, cardiorespiratory fitness, as well as greater increases in muscle mass and reduction in abdominal fat when compared to "steady-state" cardio. Definitely food for thought as you re-assess your exercise goals for 2015!
You can access the study here.
Chen, Z. -P., Stephens, T. J., Murthy, S., Canny, B. J., Hargreaves, M., Witters, L. A., . . . McConell, G. K. (2003). Effect of exercise intensity on skeletal muscle AMPK signaling in humans. Diabetes, 52, 2205–2212.
Edgett, B. A., Foster, W. S., Hankinson, P. B., Simpson, C. A., Little, J. P., Graham, R. B., & Gurd, B. J. (2013). Dissociation of increases in PGC-1a and its regulators from exercise intensity and muscle activation following acute exercise. PloS One, 8, e71623.
Hood, M. S., Little, J. P., Tarnopolsky, M. A., Myslik, F., & Gibala, M. J. (2011). Low-volume interval training improves muscle oxidative capacity in sedentary adults. Medicine & Science in Sports & Exercise, 43, 1849–1856.
Little, J. P., & Francois, M. E. (2014). High-Intensity Interval Training for Improving Postprandial Hyperglycemia. Research quarterly for exercise and sport, 85(4), 451-456.
Journal of Negative Results in Biomedicine, November 2014
I found this study interesting. Recent research has found contradictory evidence as it relates to energy drinks capacity as a performance aid. A study done on Colombian soldiers found that the consumption of caffeine and taurine (or their combination) does not increase the physical and cognitive ability in young adults during exercise. In the study, 14 volunteer male soldiers were asked to perform a battery of tests, which included: cardiorespiratory fitness (VO2max and maximum heart rate), time to exhaustion, strength (isometric strength), power (vertical jump), concentration (Grid test) and memory (Digits test) after drinking one of the following five beverages 45 minutes prior to the test: 1) caffeine, 2) taurine, 3) caffeine and taurine, 4) red bull (caffeine and taurine), and 5) placebo. The caffeinated beverages contained 80mg and the taurine beverages 1000mg. The results found that there were no significant differences when compared against the placebo group. Definitely interesting considering brands like Monster and Red Bull have always marketed the purported mental and physical benefits of energy drinks. You can access the study here.
Kammerer, M., Jaramillo, J. A., García, A., Calderón, J. C., & Valbuena, L. H. (2014). Effects of energy drink major bioactive compounds on the performance of young adults in fitness and cognitive tests: a randomized controlled trial. Journal of the international society of sports nutrition, 11(1), 1-7.