Garmin data reveals the biggest predictor of VO2 max
New data from Garmin Connect activity logs across 2025 reveals a consistent relationship between training volume and aerobic fitness. Analyzing millions of users worldwide, the reports confirm that athletes who increase their weekly mileage tend to record higher VO2 max values.
This correlation remains steady across every mileage band, suggesting that increased activity provides a reliable path toward improved cardiovascular efficiency.
The Correlation Between Volume and Performance
Among cyclists, the link between weekly distance and VO2 max is linear. Riders averaging 0-20 miles per week recorded an average VO2 max of 49, while those averaging 200 miles or more reached an average of 64.
The progression is steady throughout the reported ranges. For instance, 20-40 miles per week returned a value of 51, and the 180-200 mile band reached 62, with no obvious plateau visible in the data.
While equivalent VO2 max data by mileage was not published for runners, resting heart rate followed a similar pattern. Non-runners averaged 62 bpm, whereas those running more than 31 miles per week averaged 55 bpm.
Understanding VO2 Max and Healthspan
VO2 max measures the maximum rate the body can consume oxygen during sustained exercise, expressed in millilitres per kilogram of bodyweight per minute. It serves as the primary measure of an individual’s aerobic ceiling.
Beyond athletic performance in events ranging from 5K races to Ironmans, this metric correlates with healthspan, which is the total length of a person’s healthy life.
The data shows overall averages of 51 for cyclists and 50 for runners. Both figures generally fall within the good-to-excellent range for recreational athletes, depending on sex and age.
The Impact of Age on Aerobic Capacity
Physiological decline is a consistent factor in aerobic capacity. Among cyclists, the average VO2 max dropped from 57 in the 20-29 age group to 42 for those over 70.
This decline is driven by changes in muscle composition and reduced cardiac output. However, the relationship between training volume and improvement holds regardless of age.
Older athletes who train consistently can still improve their VO2 max and typically record higher values than sedentary peers of the same age, though their overall ceiling is lower.
Practical Applications for Athletes
The data suggests that progressively building weekly volume is the most reliable approach to increasing VO2 max. However, volume alone is not the complete solution.
High-intensity efforts, such as threshold work and intervals, provide a stimulus that easy miles cannot replicate. A combination of both volume and intensity is more effective than easy miles alone.
Athletes are encouraged to track trends rather than absolute numbers. Because estimates can be influenced by heat, altitude, or optical heart rate sensors, the direction of travel over months is more valuable than a single day’s figure.
Global Trends and Behavioral Shifts
Training habits are evolving, with indoor running activity increasing by 12.6% per user in 2025 compared to 2024. This growth is likely driven by structured indoor training and treadmill use.
Geographically, South Korean users led in total running volume, including track and treadmill categories. France was the leader in trail running activity.
Interestingly, the 50-59 age group recorded the longest average distance per session at 5.1 miles. While they run more slowly than younger groups, they cover more ground per outing.
Looking ahead, the rise in combined strength and endurance sessions may lead to a shift in how athletes structure their weekly programmes. The continued growth of indoor training could also suggest a greater reliance on controlled environments to maintain consistency throughout the year.
Frequently Asked Questions
What is a good VO2 max for a recreational cyclist or runner?
In 2025, Garmin users averaged 51 for cyclists and 50 for runners, both of which are in the good-to-excellent range. However, the most meaningful comparison is against your own age and sex cohort.
How many miles per week are needed to improve VO2 max?
Improvement was observed across every mileage band starting from 0-20 miles per week. While there is no minimum threshold, gains become more pronounced above 60 miles per week.
Why does VO2 max sometimes drop during the summer?
Heat increases the heart rate relative to pace. The algorithm interprets this as a decrease in fitness, though the number typically recovers once temperatures cool and new baselines are established.
Do you prioritize weekly mileage or high-intensity sessions when tracking your fitness progress?