Updated: Nov 24, 2022
Too Much High Intensity Cycling?
High intensity interval training has long been a popular choice for cyclists looking to improve their fitness with limited time available, as intensity can, if handled correctly, be more effective than traditional steady-state cardiovascular riding in terms of improving VO2 max and burning calories. BUT, when it comes to high intensity workouts, more is not necessarily better. In fact, recent research has shown that too much high intensity can lead to “sudden and severe declines in the function of mitochondria, which are the energy powerhouses inside the cells, along with incipient signs of blood sugar dysfunction”. On a more tangible level, too much intensity in your plan can lead to overtraining and all that comes with it: loss of performance, loss of motivation, depression, irritability, insomnia and numerous other suboptimal impacts! I’ve been there personally, it’s a dark rut that can take a long time to come out of!
So how much high intensity interval training should you be doing? If you're a relatively new cyclist, you'll want to stick to shorter intervals at lower intensities. As you become more experienced and resilient, you can increase the length and intensity of your intervals.
For veteran athletes, high intensity intervals play a crucial role in countering the ageing process (loss of lean muscle mass and decrease in VO2 Max), but, recovery between sessions must be longer versus a cyclists in their late 20s, for example. This doesn’t necessarily mean time off the bike, it might simply be more endurance riding in between hard sessions.
Where you are in your annual training plan always plays such a crucial part of the decision making process. For the majority of cyclists, peaking during race season is the goal. The key to peaking is including very demanding sessions at just the right time, usually about a month out from target. As such, racking up a load of intensity in the early or mid base phase is a bad idea- you’ll peak too soon and likely hit race day tired.
How you respond as an individual athlete is probably the most important factor to consider. There are some riders who are hugely resilient to intensity and can bounce back from 4 or more hard sessions per week. Conversely, there are riders who can hit massive numbers in a single session but need 5 days to return to freshness. Muscle fibre type is said to play an important part in this individual response. Thus, there is certainly an element of trial and error when creating an individualised intensity structure, but erring on the side of caution is advisable.
Fundamentally, these intervals must be stacked upon a base of solid endurance. If you go straight into the season with block of VO2 efforts this is likely a one way ticket to burn out, and, if this fatigue is not shed with some prolonged rest, it can subtly follow you throughout the whole season resulting in a string of inconsistent performances. In short high intensity absolutely has its place in almost every training plan. But, timing, experience, age and individual response are important considerations before launching into a hard block of training.