CrossFit vs Running: evidence from High Intensity Interval Training.
Endurance exercise is recommended for cardiovascular health. High Intensity Interval Training (like CrossFit) shows promising results. Years of research have found that about 30 minutes of cardio will reduce risk of stroke and heart attack. It will also improve insulin sensitivity, reduce risk of diabetes and improve memory and brain function. Until very recently, there has been little research on the benefits of CrossFit type exercise on health. These studies focus on High Intensity Interval Training. High Intensity Interval Training consists of multiple sets of intense exercise that last 1-4 minutes. These are spaced with short rest periods. Or periods of light exercise. Research on this approach to exercise indicates that this approach may be better than running (or other sustained types of cardio) in a number of ways. These include cardio and respiratory fitness. And also insulin sensitivity and arterial stiffness. Arterial stiffness is an indicator for risk of cardiovascular disease. It is also looking like High Intensity Interval Training may be better at controlling or preventing high blood pressure than the traditional 30 minutes of sustained cardio.
Is CrossFit better than running?
The question of is CrossFit better than running is not known yet. And CrossFit is different than the types of High Intensity Interval Training being tested. In a nutshell, CrossFit is a fitness program that involves high intensity exercise. Many different muscle groups are targeted in a CrossFit workout (also known as a CrossFit WOD.) Workouts may last 5-20 minutes and involve springs, weight lifting, pull-ups and other bodyweight exercises. If you are wondering “what is CrossFit” try this link. CrossFit exercises may or may not include periods of rest between sets. However, there is a lot of shifting of focus. Intensity may be sustained, but not sustained on the same muscle groups. This might be better for vascular health.
CrossFit vs Running: More research needed
Short periods of high intensity exercise improve capillary growth. This allows for greater blood flow to tissues. Including muscle. It is possible that intense exercise impacting multiple muscle groups would be better than exercise that impacts only legs (as in running). This is an exciting area of research. It will be interesting to see what comes up next. Hopefully more research will be done soon that will look at whether or not CrossFit or High Intensity Interval Training does as well with brain health and control of diabetes.
For a look at recent papers take a look at:
Cocks, M., Shaw, C., Shepherd, S., Fisher, J., Ranasinghe, A., Barker, T., Tipton, K., & Wagenmakers, A. (2012). Sprint interval and endurance training are equally effective in increasing muscle microvascular density and eNOS content in sedentary males The Journal of Physiology, 591 (3), 641-656 DOI: 10.1113/jphysiol.2012.239566
Spence AL, Carter HH, Naylor LH, & Green D (2013). A prospective randomised longitudinal study involving 6-months of endurance or resistance exercise on conduit artery adaptation in humans. The Journal of physiology PMID: 23247114