What is zone 2 training?
Zone 2 training is light endurance exercise just below your first threshold, popular among (elite) endurance athletes, but for the general population with limited time it is probably not the most efficient approach: higher intensities appear to yield greater returns in that context.
Zone 2 training is endurance training at an intensity just below your first lactate or ventilatory threshold. That is the point at which your body just begins to shift from fat to carbohydrates as its primary fuel. In terms of feel: you can still hold a conversation, but it does not come effortlessly. A panel of 14 exercise scientists and coaches confirmed this definition and noted that sessions can be performed continuously, in varied formats, or as intervals.
A word of caution: the term itself is confusing. In scientific literature that uses three intensity zones, 'zone 2' refers to the band BETWEEN the two thresholds, which represents a fairly substantial effort. Popular media and podcasts, however, use 'zone 2' to mean the light intensity BELOW the first threshold. It is worth asking which definition someone is using.
Elite endurance athletes spend on average around 75-80% of their training time at this low intensity and 15-20% at high intensity. Observational research across multiple sports consistently finds this pattern. A randomised study in recreational to sub-elite runners showed that the group training more than 80% of the time below the threshold improved their performance by 157 seconds over five months on a 10.4 km distance, compared with smaller gains in the group that spent more time training between the thresholds.
That said, zone 2 is not a magic bullet for everyone. A narrative review concludes that the current evidence does not support zone 2 training as the best intensity for improving fat or mitochondrial metabolism in the general population. People with limited time to train will likely achieve greater health benefits at higher intensities. Furthermore, the physiological adaptations from zone 2 training are probably not unique to this zone and also occur at slightly higher or lower efforts.
Based on a consensus panel (n=14 experts), two observational datasets in elite athletes, a randomised study in recreational runners, a systematic review, and a narrative review. Observational evidence predominates; the randomised study concerns one specific running distance.
How much zone 2 training do you need per week?
There is no researched minimum for zone 2 in recreational athletes, but patterns in elite athletes show that low intensity fills the majority of training volume and that removing it comes at a cost to fitness. If your training time is limited, focus on building a broad base of low-intensity work and only add high intensity once that base is in place.
How do you determine the right amount of Zone 2 training without fatigue sabotaging your progress?
There is no hard universal formula for the right amount of Zone 2 training, but lactate as a control tool (target zone 2-4.5 mmol/L) offers a more concrete guide than pace or heart rate alone. Build volume gradually and pay attention to signals such as heart rate variability to monitor fatigue.
How much rest do my muscles need between workouts as I get older?
Getting older does not call for more rest, but for more regular training: at least two resistance-training sessions per week, supplemented with adequate protein, is the best-supported approach for counteracting muscle loss.
What is the best training to prevent muscle loss after age 60?
Strength training, combined with adequate protein intake, is the best-supported strategy against muscle loss after age 60. If you also want to lose weight, add endurance training to better protect muscle mass.
What is VO2max and how important is it for living longer?
A higher VO2max is strongly associated with a longer life, though exercise itself is probably at least as important as the number. Regular movement, even light activity, pays off at every age.
Does stretching actually help, or is it a waste of effort?
Stretching demonstrably improves flexibility, and 10 minutes per week is already enough for the maximum effect. For preventing injuries, however, it does not work; eccentric strength training is far more effective for that purpose.