When you are deciding between active rest (lower intensity workouts- around 60% of max) and inactive rest there are a couple of factors to consider including phase of training cycle and type of exercise. One study did show that active recover during a cycling power test yielded better power performance than a still rest period in between testing bouts. This study was looking at rest between close bursts of energy expenditure and not monthly exercise programs. Another study involving rugby players that researched the affects of an active rest found that “the addition of low intensity exercise to the rest period did not adversely affect physiological recovery and had a significantly beneficial effect on psychological recovery by enhancing relaxation.” A good form of active rest may be cross training. So if you are a triathlete take a break from swimming, biking, and running and do a strength or stretching workout.
You can do a mini self assessment to see if you are in need of a rest day. Signs that you may need a rest day include: irritability, low energy, trouble sleep, illness, nagging injuries, and/or difficulty maintaining a steady heart rate. Your body does a pretty good job at telling you how it is doing; we just have to be better listeners! So do not feel guilty for taking a rest day; your body needs them periodically! Enjoy your summer training!
Eyeston, Ed. The rest is easy: why you have to back off in order to push hard. April 2, 2009. http://www.runnersworld.com/running-tips/rest-easy.
Halson SL, Bridge MW, Meeusen R, Busschaert B, Gleeson M, Jones DA, Jeukendrup AE. Time course of performance changes and fatigue markers during intensified training in trained cyclists. Journal of Applied Physiology. 1 September 2002. Vol. 93no. 947-956DOI: 10.1152/japplphysiol.01164.2001. http://bjsm.bmj.com/content/38/4/436.abstract.
Signorile JF, Tremblay LM, Ingalis C.The Effects of Active and Passive Recovery on Short-Term, High Intensity Power Output. Canadian Journal of Applied Physiology, 1993, 18(1): 31-42, 10.1139/h93-004
Suzuki M, Umeda T, Nakaji S, Shimoyama T, Mashiko T, Sugawara K. Effect of incorporating low intensity exercise into the recovery period after a rugby match. Br J Sports Med2004;38:436-440 doi:10.1136/bjsm.2002.004309