Zone 2 Cardio Is Boring and That's the Point

The strongest signal in the sleep literature is also the least glamorous: regularity. Going to bed and waking at consistent times appears to matter as much as total duration for metabolic and cardiovascular markers. The lever most people can actually pull is not a gadget but a fixed wake time, weekends included.

Low-intensity, sustainable cardio — the pace at which you can still hold a conversation — builds the aerobic base that everything else rests on. It is unglamorous and slow to show results, which is precisely why it is under-practiced, and why the people who stick with it quietly outperform the ones chasing intensity.