Tools & Resources
Every tool I actually use or have tested — scored for evidence quality. No pay-to-play. If I don't believe it works, it's not here. Some links are affiliate links which help support HAKD at no cost to you.
Finger-based PPG gives the cleanest overnight HRV data. No subscription required for core features. Validated sleep staging. Best all-around choice if you want one device.
Strain score is the most useful periodization signal of any wearable. Tracks recovery vs. exertion across every workout automatically. No screen — pure data.
HRV Status feature tracks 5-night rolling average and surfaces training readiness. VO2 max and aerobic/anaerobic training load baked in. Best choice if you train outdoors.
Autopilot adjusts bed temperature by sleep stage throughout the night. Built-in HRV tracking eliminates need for a wearable. Measurably improves deep sleep in most users within 2 weeks.
Chills to 39°F, filtration keeps water clean without constant draining, durable build. If you're going to cold plunge consistently, this is the setup that doesn't become a maintenance project.
NSF Certified for Sport. Full label transparency, no proprietary blends, clinical doses across every product. If you buy creatine, omega-3, collagen, or magnesium — buy them here.
One scoop fills diet gaps: greens, adaptogens, probiotics, vitamins. Not a performance optimizer — a gap-filler. Best ROI if your diet is inconsistent or you travel frequently.
NSF Certified. Used by pro sports teams. Best source for vitamin D3/K2, fish oil, zinc, and magnesium if you're building your own stack instead of buying bundles.
Engages the most muscle mass of any cardio machine (legs, back, arms), maximizing mitochondrial stimulus per session. Built for Zone 2 precision. Lasts decades.
Neural oscillation technology that actively entrains focus states — not just background music. Multiple published studies. Best for 2–4 hour deep work blocks.
Real-time glucose shows how your meals, workouts, sleep, and stress actually affect metabolic health. The most underused performance biometric available to consumers.
Same CGM sensor data as Levels, but includes monthly sessions with an RD who interprets your glucose patterns and adjusts recommendations. Best if you want guided metabolic coaching.