As promised, I've got a new blog post ready for your reading. This one has been written to help answer one of the most common questions I get asked regarding the Occlusion Cuffs: are they safe?
I always say it's a great question and one I would hope anyone intending to try out a new training method would ask. I would much rather have conscientious and informed customers who are using the cuffs in a safe and sensible manner, rather than the alternative. It's also one of the reasons that the product was created - to provide a better option for injured athletes and gym-goers other than the crude bands and straps that are available. By being able to monitor the pressure and be able to determine a safe training zone to work in is very important.
So what does the scientific evidence have to say regarding the safety of Occlusion training? Well, the bottom line is that it is just as safe as normal resistance training. Occlusion or blood flow restriction training carries no greater risk than regular exercise. This conclusion has come from a huge study by Nakajima et al., (2006) that collected data from 30,000 occlusion/BFR training sessions in 105 facilities Japanese facilities. They found that although there were some very rare incidences of concern, that these were actually occurring less frequently in people using BFR training than in the general population.
One of the main concerns that we see is the speculation regarding blood coagulation. However, Nakajima followed up on the national survey with a study on the effect of occlusion training on haemostasis, which found that, contrary to what some people assumed, occlusion training did not increase fibrin formation of D-Dimer presence. In fact it appeared to positively influence the production of cardio-protective markers via fibrinolytic stimulation. This has been supported by evidence from Madarame et al., 2010 who found that blood samples taken before, 10 minutes after, 1 hour, 4 hours, and 24 hours after showed no increase in thrombin markers or intravascular clot formation. Clark et al., (2011) further supported this evidence when their study found that occlusion training did not negatively alter peripheral vascular stiffness, peripheral nerve conduction, or blood clotting function. Therefore, there is a possibility that in the future occlusion training may be used to actually improve circulation in certain populations.
Jeremy Loenneke, the most prominent researcher in the field, conducted a review in 2011 on the potential safety issues of occlusion training. His extensive search also found that the studies agree on the fact that peripheral blood flow responds similarly to occlusion training as it does to normal training and that there is no oxidative or nerve conduction stress risk with occlusion training. This can be concluded from a range of 80+ studies and Loenneke states that this is ‘regardless of age and training status'. One explanation of this is that the effects of occlusion training on the restriction of blood flow are very acute, and as Fred Aylward has shown, the system returns to normal very quickly.
Recently, in 2014 Araújo et al., looked at the effect of occlusion training on blood pressure and found that occlusion training is more effective than moderate level resistance training (it was knee extensions, with and without occlusion) at reducing blood pressure in hypertensive individuals. So the evidence for the safety and even beneficial influence of occlusion training s continuing to roll out and I'm sure we'll see even more along these lines.
It is very reassuring research for anyone concerned about the mechanisms of occlusion training. All the evidence suggests that the coagulation system is not activated with occlusion training and it may even provide a beneficial effect for reducing peripheral resistance. However, please do still practice caution, discuss occlusion training with your doctor beforehand, and if in any doubt consult an medical expert in the field.