+ When You Should Do VO2 Max Intervals

As a Coach, I have my 1x1 coached athletes abstain from traditional VO2 max intervals until they are six weeks out until their goal event, race or group ride season.

Why?  3 reasons:

  1. Building base is so important and you can’t build base when you are trying to do quality VO2 work.
  2. To Minimize Mental Fatigue and Motivation
  3. Half-Life of VO2 benefits - the benefits from doing VO2’s in February are gone by April, so why even do them if you are training for an event after that? Timing is everything and so is proper periodization. 

There is a caveat and thus this training tip: the scientific literature supports VO2 work year-round while also pointing out the drawbacks (overtraining, monotony, & mental fatigue)

The solution that I have found to work from coaching athletes for 22 years is a technique called “micro dosing”.  Micro dosing is the sprinkling in of ‘time in zone’ vo2 max intensity.  This time in zone micro dosing can be achieved 3 ways:

  1. organically on a spirited group ride
  2. with over under and criss cross intervals 
  3. traditional vo2 interval sessions

For amateur athletes, I prefer the once a week, spirited group ride and a 4 week block of once a week over unders and criss cross intervals (found in our 16 weeks of sweet spot training plan). Micro dosing VO2 work on group rides keeps the mental load low and the fun factor high. 

Micro-Dosing is a sport science term and training technique in cycling that involves performing short, high-intensity intervals designed to stimulate specific physiological adaptations—like VO2 max—without causing excessive fatigue or incurring mental load. 

These efforts are typically 30 seconds to 2 minutes at high intensity (e.g., 120-130% of FTP), with equal or slightly longer recovery periods. The goal is to accumulate time at high oxygen uptake levels while keeping the session manageable and repeatable. Micro-dosing is ideal for busy athletes or those looking to benefit from VO2 adaptations during the base & taper phases of an annual training plan. 

It’s a “less is more” approach, focusing on quality over quantity to reap the benefits of year round Vo2 Max workout without the mental and physical fatigue. 

Scientific research consistently proves that VO₂-max (i.e., high-intensity) training for endurance cyclists is beneficial, but the question of how and when to include these sessions throughout the year is critical. High-intensity interval training (HIIT) has been shown to improve maximal aerobic capacity and increase the fraction of VO₂-max utilized at submaximal intensities, which can ultimately boost endurance performance (Laursen & Jenkins, 2002; Buchheit & Laursen, 2013).

To maximize VO₂-max benefits, most literature (e.g., Seiler, 2010; Mujika, 2013) suggests that cyclists emphasize lower-intensity, higher-volume training during the base phase then introduce VO₂-max–specific intervals in targeted blocks later in the season. In practice this is our 16 weeks of sweet spot base phase followed by a six week interval phase. 

During the base phase,  micro doses of high-intensity efforts—the ones we see from spirited group rides, provide just the right amount of maintenance adaptations without the risk of overreaching nor mental fatigue.  (Seiler & Tønnessen, 2009; Issurin, 2010).

The Bottom Line:

In summary the science literature says VO2 Max intensity is beneficial year-round but can be micro-dosed during the base phase.  Studies from Seiler & Tonnessen also point out risk factors of too much mental fatigue and overreaching if one were to do traditional VO2 Max Intervals, year-round.

The coaching solution is to include low volume high intensity VO2 intensity in the base phase which is also known as, micro-dosing. 

Overall, periodization and the timing of VO2 Max work is a must for athletes.   Year-round VO2 Max benefits may be achieved from micro-dosing during the base phase. Then traditional interval workouts (2 sets of 2 x 5 min On 5 min Off, for example) during an interval training phase six weeks prior to competition are extremely beneficial. 

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