Real cardio fitness is built on an unglamorous recipe: a weekly base of mostly-easy "zone 2" work you could hold a conversation through, seasoned with one or two genuinely hard interval sessions — and the scoreboard is a resting heart rate that trends down over months. Most people invert the recipe, doing every session at a medium-hard grind that is too hard to build the base and too easy to sharpen the top.
Here is how to get the mix right, and how heart-rate data — the centre of heart-rate training at Coresa — takes the guesswork out of it.
Zone 2 and intervals: two jobs, two intensities
Zone 2 is conversational effort — full sentences possible, almost suspiciously easy. Held for sustained stretches, it builds the aerobic machinery: a heart that moves more blood per beat, denser capillaries, muscle that burns fuel efficiently. Intervals are the opposite tool: short, honest efforts near your ceiling that raise the ceiling itself.
You need both, in wildly unequal amounts — the bulk of your weekly minutes easy, a small slice hard. The muddy middle between them is not useless, but a steady diet of it delivers neither adaptation well while accumulating fatigue like the hard stuff.
Resting heart rate: the cheapest fitness test there is
As aerobic fitness improves, the heart needs fewer beats at rest — so a resting heart rate drifting downward across months is direct evidence the training is working. Measure it the same way each time (morning, before coffee, still in bed is the classic) and read the trend rather than the day; poor sleep, stress, or a brewing cold will all push it up temporarily.
A second scoreboard worth watching: how fast your heart rate falls in the minute after a hard effort. Quicker recovery between intervals is fitness you can watch arrive week by week.
Why heart-rate data beats feel in a group room
Perceived effort lies in company: beside fitter people you push your "easy" into the muddy middle, and on flat days you label a modest effort maximal. Heart-rate training — the studio's immersive music, lighting, and heart-rate training experience — settles the argument with data: your zones are calculated from you, displayed live, and indifferent to whatever the next station over is doing. Easy days stay honestly easy; intervals get verified hard. The HIIT classes page walks through what the zones mean mid-class.
Build the engine on more than one machine
A treadmill is one tool, not the definition of cardio. Coresa sessions spread conditioning across treadmill efforts and mixed circuit stations — the same cardiovascular demand carried by different limbs and skills. The variety spares your joints a single repetitive pattern, keeps sessions interesting enough to sustain for years, and produces fitness that transfers to Grouse switchbacks and SeaBus-catching jogs alike.
North Vancouver's long wet season makes the indoor option more than a convenience: from roughly November through March, the conditioning sessions that actually happen are the ones the weather cannot veto. Summer belongs to the trails and the seawall; an indoor base is what carries the other half of the year.
How much cardio is enough?
Global health guidance points one direction: adults benefit from a few hours of moderate activity spread across the week — or roughly half that at vigorous intensity — alongside a couple of days that strengthen muscle. That is the health floor, not a fitness ceiling; beyond it, add gradually, because consistency across months outweighs any single week's totals. Two to three coached sessions plus daily walking puts most people comfortably in range.
A week that covers both intensities without swallowing your calendar:
- One or two coached sessions carrying the hard minutes — intervals verified by heart rate, not vibes
- One longer easy effort: a brisk hill walk, an unhurried jog, a relaxed conversational session
- Everyday movement stitched through the rest — stairs taken, errands walked, the hill home climbed on foot
Common questions
How long until my resting heart rate drops?
Meaningful change typically shows across one to three months of consistent training, though between-effort recovery speed often improves sooner. A resting rate that climbs and stays elevated despite training is a flag for under-recovery or illness — worth a professional conversation if it persists.
Is walking enough to build cardio fitness?
It is a genuinely good base — brisk walking, especially on North Vancouver's hills, is real zone-2 work for many people. What walking rarely supplies is the near-ceiling stimulus that raises your top end, which is why pairing daily walks with one or two hard sessions works so well.
Are intervals safe if I'm quite unfit right now?
Intervals scale — the fittest and newest person in the room each work near their own ceiling, and heart-rate display makes that visible. Truly deconditioned exercisers should bank a few easy weeks first, and anyone with cardiac or medical concerns should get a physician's go-ahead before high-intensity work.
Does lifting weights count toward my cardio?
Not really — strength sets spike heart rate briefly but don't hold the sustained demand that drives aerobic adaptation. That is exactly why our circuits interleave resistance stations with conditioning blocks: both systems get trained in one visit instead of competing for your week.
