You’d had a great run out, the legs were firing, your watts were up, and your head-unit’s estimate of your VO2 max was the highest it’s been in months. Then life happens: a busy spell at work, a family holiday, a niggling injury and suddenly the five rides a week became two, then one. The worry became not so much how much fitness you were losing, but whether you’d ever get it back.
“From my experience, maintaining VO2 max takes less work than improving it,” explains Paul Mill, London-based owner of Elite Cycling and former head coach to Team Wiggins. “Once you’ve built a strong aerobic engine, you don’t need to keep pushing the same training load year-round to hold onto most of those gains.”
It’s reassuring to hear, but what about maintaining those levels when you’ve had an enforced break from your regular training – or have been struggling to find the time? “I work with lots of time-crunched athletes,” adds Mill. “One of the major factors in maintaining good fitness in less time is by hitting higher intensities above VO2 max.”
(Image credit: Andy Jones)
Mill contends that while training volume certainly contributes to endurance performance, VO2 max itself responds very well to relatively short periods of high-intensity work. “After a period of lower volume, riders notice a difference in endurance – they may still have the same aerobic capacity, but they’ll lose some fatigue resistance and the ability to sustain power for longer durations.”
When training drops off, even if VO2 max remains stable, performance over longer distances declines. Cody Stephenson, a programme manager at Training Peaks, says there’s an important distinction between losing peak fitness and losing your aerobic base. “You lose top-end faster than you gain it, but you lose lower-end gains much slower than you originally earned them. If you think of fitness as a pyramid, the closer you get to your personal ceiling, the harder each additional improvement becomes.”
When an untrained rider starts exercising, the gains come fast, but once trained, extracting the final few per cent of potential VO2 max can take years of consistent training. “The same applies in reverse,” says Stephenson. “Stop training when you’re at your absolute peak and that last, hard-earned layer can disappear surprisingly quickly, though your underlying fitness doesn’t immediately collapse with it.”
Losing a little fitness during a busy period is very different from stopping completely and having to rebuild everything later
Cody Stephenson
Stephenson’s point is important for amateurs because it makes maintenance an attractive strategy. Losing a little fitness during a busy period is very different from stopping completely and having to rebuild everything later. “The perception that you lose fitness faster than you gain it is because you lose that last, hard-fought peak pretty quickly,” he says. “But to go from 100% to 0% completely will take about as long as going from 0% to 100%.”
Why does V02 max drop off when we stop training?
Understanding how fitness is built and maintained helps riders better predict how quickly a lay-off will impact their peak VO2 max. “VO2 max starts to fall within the first week or two of stopping, and the early losses are surprisingly steep,” explains Professor Sebastian Sitko from the University of Zaragoza, Spain. “Research suggests a decline of roughly 5-7% within two weeks of complete rest, reaching around 10% by five weeks and potentially 15-20% after two to three months.”
Professor Sebastian Sitko
Sebastian Sitko is a sport scientist, pro cycling coach and professor at the University of Zaragoza, Spain. He conducts field-based research into cycling performance.
Sitko has taken a personal interest in this particular topic. As an endurance coach, sports scientist, university lecturer and author, he faces a similar challenge to so many of us – finding the time to enjoy his passion, and keeping up the level of performance he feels makes it all worthwhile.
(Image credit: Future)
He explains how the losses set in. “The earliest and fastest loss is central and haematological: within days, you lose plasma volume – a 10-12% fall in the first two to four weeks – which reduces blood volume, which in turn lowers stroke volume, and therefore the amount of oxygen your heart can deliver per beat.”
That single mechanism explains most of the first few weeks of VO2 max decline. Only later, roughly from the third week onward, do the peripheral, muscle-level adaptations regress. “That’s the mitochondrial enzyme activity-citrate synthase can fall 25-40% over a few weeks – and, more slowly, capillary density,” adds Sitko.
In layman’s terms, your aerobic plumbing-blood volume, stroke volume – drains quickly and is regained quickly, whereas the muscle machinery is both slower to build and somewhat slower to lose. “That asymmetry is why it feels like fitness evaporates faster than it arrives.”
INTENSITY RESTORED MY VO2 MAX
Nicola Toms, 56, a sculptor from London, began as a recreational cyclist struggling to find time to train consistently. She has worked with coach Paul Mill through some major challenges.
“Within two and a half years, I went from riding with Velcro reflective ankle straps to becoming a World Masters track champion. After joining the Aprire racing team, I continued racing until a serious accident ended my racing.
“Paul Mill supported me through rehabilitation back to consistent training. To rediscover and maintain my VO2max, my training combines live online turbo sessions and road riding with the emphasis on aerobic conditioning, threshold, high intensity work, strength, mobility and stretching. Paul conducts FTP testing on Velocity every eight to 12 weeks to ensure my training zones are accurate and I’m training at the right intensities.”
Both Sitko and Stephenson agree on the central principle: intensity becomes disproportionately valuable when training time is limited. Sitko also points to foundational research by Hickson RC et al. from 1981, which showed that once VO2 max has been established, training frequency can potentially be reduced to two sessions per week and training volume substantially reduced, while maintaining VO2 max, provided intensity is preserved.
“The non-negotiable ingredient is intensity, not mileage,” says Sitko. His practical minimum for maintaining VO2 max is roughly one to two sessions per week incorporating high-intensity work near VO2 max. “That could mean four to six repetitions of three to five minutes hard, or sessions such as five five-minute efforts. In total, that might amount to just 15-30 minutes of high-intensity work in a week.”
Three sessions a week, if optimised, should work for most people
Cody Stephenson
Stephenson is slightly more conservative, suggesting that three intensity-targeted sessions per week would be a safer maintenance target for most riders. “Two should be hard VO2 max-focused sessions, such as four-by-four-minute or five-by-five-minute intervals, or shorter micro-intervals such as 40 seconds hard followed by 20 seconds easy.”
In terms of total high-intensity volume, Stephenson recommends 20-45 minutes each week between threshold and VO2 max intensity; the third session would be lower intensity, ideally a couple of hours at endurance or Zone 2 pace.
“This is going to vary immensely from person to person based on age, sex, nutrition, sleep, and most importantly genetics, as there is a lot of variation in how responsive people are to training. But if I were to make a safe estimate that should work for the majority of people, I’d say three sessions a week, provided they are optimised.”
V02 max isn’t the same as endurance
A word of warning: a rider can maintain a very respectable VO2 max while losing a significant amount of long-range endurance. “VO2 max is a ceiling,” explains Sitko. “But your ability to use a large fraction of that ceiling for hours is a different set of adaptations.” Those adaptations include mitochondrial density and oxidative enzyme activity, capillarisation, fat oxidation, glycogen sparing, plasma volume and the muscular conditioning required to keep producing power late in a ride.
Stephenson sees the same effect in amateur riders who specialise in shorter events such as track, criterium or cyclo-cross racing. “They typically don’t have as much time available to train overall, so they have to really focus on their race-relevant systems, like VO2 max,” he says. The result can be a rider who is extremely effective over a short race but struggles when asked to ride continuously hard for two or three hours.
In Stephenson’s experience, amateur track and cyclo-cross racers sometimes find that their two-to three-hour Zone 2 rides begin to feel disproportionately difficult – even when their racing form is high. The problem isn’t that their VO2 max has collapsed. Rather, their endurance efficiency and fatigue resistance have deteriorated. Sitko describes this as durability – the ability to maintain power as fatigue accumulates.
“I think the physiological systems that suffer the most when volume drops are overall efficiency,” says Stephenson. “Things like efficiency factor (EF) and decoupling (Pw:HR) in Training Peaks. There are a lot of factors that go into endurance efficiency, but things like heat accumulation tolerance and fat utilisation rate are big parts.”
(Image credit: Andy Jones)
Age complicates the equation, but perhaps not in the way you might expect. VO2 max declines with age, with one major reason being the gradual reduction in maximum heart rate – roughly 0.7 to one beat per minute per year, on average. Loss of muscle mass also becomes increasingly important because there is less tissue available to extract and use oxygen.
Does this mean older riders need to compensate by upping their volume? Sitko thinks not. “Older athletes must protect intensity and add resistance work,” he says, specifying that this is the recipe to slow down losses as effectively as possible.
Stephenson agrees with Sitko that VO2 max-maintenance for older riders doesn’t oblige them to increase their training volume. “They just need to be more focused,” he says. Young riders can often get away with what he describes as “unfocused hours” – riding plenty, sleeping imperfectly and eating poorly, yet still improving because youthful physiology is forgiving.
“If you want to maintain VO2 max as much as possible,” says Stephenson, “you have to do regular, consistent, optimised VO2 max-focused training and do all the supportive work – good sleep, good nutrition, good workout timing and strength training.”
What’s the best way to track our V02max?
VO2 MAX: WHAT COUNTS AS ‘GOOD’?
Coach Paul Mill stresses that context is important – VO2 max is far from the only determinant of performance – but his research-based benchmarks for recreational cyclists are:
Age 30-39
Men: Good 50-55, Excellent 56-62, Superior 63+
Women: Good 42-47, Excellent 48-54, Superior 55+
Age 40-49
Men: Good 47-53, Excellent 54-60, Superior 61+
Women: Good 39-45, Excellent 46-51, Superior 52+
Age 50-59
Men: Good 44-50, Excellent 51-57, Superior 58+
Women: Good 36-42, Excellent 43-48, Superior 49+
Age 60-69
Men: Good 40-46, Excellent 47-53, Superior 54+
Women: Good 33-39, Excellent 40-45, Superior 46+
Values are ml/kg/min.
The easiest way most riders monitor their VO2 max is to glance at their bike computer or GPS watch. But how seriously should you take the number? Prof Sitko says validation studies have produced strong correlations between wearable estimates and laboratory values at group level, but individual errors can be large.
“The algorithms can also systematically underestimate very fit riders and overestimate less-fit ones. Some years ago I led a study showing we can predict cycling VO2 max reasonably well with a five-minute test. Validation studies show these devices are fairly accurate overall. When paired with a chest-strap heart-rate monitor, the numbers track very closely with proper lab tests, usually sitting within just 3 to 5ml/kg/min of the true value.”
The catch is that individual readings can be off by up to 15%. The software essentially drags everyone toward the middle – shortchanging highly fit riders while flattering the less fit.
In any case, the direction of travel matters much more than the absolute figure, in Stephenson’s view. “[Smart-watches] are consistent and directionally reliable,” he says. In other words, don’t worry too much if your watch says your VO2 max is 52 when a laboratory test might say 49. If the number consistently rises alongside improvements in your three- to eight-minute power, you can trust the trend is correct.
Doing a proper V02 Max test involves a ramp test in lab conditions
(Image credit: Future)
A laboratory CPET test still has its place. It’s worthwhile if you need an accurate absolute value, want highly precise training zones, have an unusual maximum heart rate that could undermine a wearable estimate, or simply want a comprehensive physiological assessment. For everyone else, Sitko’s advice is to trust the watch for direction; trust the lab for the actual number.
Which brings us back to personal aims, goals and focus around VO2 max maintenance. If your priority is maintaining VO2 max, a surprisingly small amount of high-quality intensity can do much of the work. But if you want to remain capable of riding hard for several hours, you still need some longer, easier work to protect endurance and durability.
For a cyclist with only a few hours available each week, that might mean prioritising two quality interval sessions, adding an endurance ride when possible and resisting the temptation to fill every spare minute with medium-hard riding. And when life gets in the way, don’t assume a reduced week is a disaster. Protect the key sessions, preserve some intensity and keep the aerobic volume as high as the diary will allow.
