Lifestack combines biometric data, calendar signals, and screen time into actionable intelligence. Every weight, threshold, and multiplier is grounded in peer-reviewed research.
Algorithm 01
A 0-to-100 composite representing how much your body can handle today. A battery percentage for your autonomic nervous system.
Why HRV is weighted heaviest. Heart rate variability is the single strongest non-invasive marker of autonomic recovery, correlating with stress tolerance, faster recovery, and better cognitive performance. 1, 2
Personal baselines, not population norms. Absolute HRV varies wildly between individuals. Lifestack normalizes every metric to your 30-day rolling average so the score reflects deviation from your own baseline. 3
1. Shaffer & Ginsberg (2017). Frontiers in Public Health, 5, 258.
2. Plews et al. (2013). Int. J. Sports Physiology, 8(6), 688-694.
3. Bellenger et al. (2016). Sports Medicine, 46(10), 1461-1486.
As seen in Lifestack
Focus timeline sample
Algorithm 02
Measures the quality of your digital attention. Not hours logged, but how deeply you used them.
23 minutes to refocusafter each interruption. Fragmented work increases stress and reduces accuracy. 4
Attention residuefrom the previous task reduces performance by ~20%, even when you believe you've fully transitioned. 5
7 switches/hour threshold.Above that, the switching penalty scales linearly. Derived from research showing knowledge workers switch tasks every 12 minutes on average. 6, 7
4. Mark, Gudith & Klocke (2008). CHI '08, ACM.
5. Leroy (2009). Org. Behavior and Human Decision Processes, 109(2).
6. Newport (2016). Deep Work. Grand Central Publishing.
7. González & Mark (2004). CHI '04, ACM.
Algorithm 03
Warns you when scheduled commitments exceed biological capacity. Your calendar should respect your body.
Rooted in demand-control theory. Adapts Karasek's model: high demand + low control = highest stress and health risk. Calendar load is demand; biological capacity is control. 8
23% higher coronary risk. A meta-analysis of 228,394 participants found that the demand-control imbalance Collision Detection measures significantly increases heart disease risk. 9
8. Karasek (1979). Administrative Science Quarterly, 24(2), 285-308.
9. Kivimäki et al. (2012). The Lancet, 380(9852), 1491-1497.
Collision warning sample
Severe collision detected
Capacity 34 vs load 78%. Consider rescheduling Strategy Session.
Exhaustion calculator sample
lost to low-capacity work hours
Based on $150/hr rate, 6h low-capacity work/week
Algorithm 04
The core finding
Chronic sleep restriction to 6h/night for 14 days produces cognitive deficits equivalent to two nights of total sleep deprivation, while subjects consistently underestimate their impairment. 10
The 0.6x multiplier.Below capacity 50, every hour returns ~40 cents on the dollar. Derived from meta-analytic findings: sleep deprivation reduces cognitive performance by ~1 standard deviation. 11
$411 billion annually.RAND found insufficient sleep costs the US economy this much in lost productivity. Per worker: ~11 productive days lost per year. 12
You don't notice your own decline. Subjective sleepiness plateaus after a few days while objective performance continues to degrade. You feel fine. You're not. 10
10. Van Dongen et al. (2003). Sleep, 26(2), 117-126.
11. Pilcher & Huffcutt (1996). Sleep, 19(4), 318-326.
12. Hafner et al. (2017). RAND Corporation, RR-1791-VH.
Cross-Domain Insights
The most powerful insights emerge where health, time, and finance overlap.
5h
sleep
+$28
impulse spend
Sleep deprivation shifts financial decisions toward riskier choices, underweighting losses while overweighting gains. 13
fMRI research: poor sleep amplifies brain regions driving food desire while suppressing evaluative frontal regions. 14
13. Killgore et al. (2006). Sleep Medicine, 7(5).
14. Greer, Goldstein & Walker (2013). Nature Comms., 4.
The post-lunch alertness dip is circadian, not dietary. It occurs regardless of food intake and is amplified by poor sleep. Lifestack detects when low HRV coincides with this window. 15
15. Monk (2005). Clinics in Sports Medicine, 24(2).
1. Shaffer & Ginsberg (2017). "HRV Metrics and Norms." Frontiers in Public Health, 5, 258.
2. Plews et al. (2013). "HRV in Elite Athletes." Int. J. Sports Physiology, 8(6).
3. Bellenger et al. (2016). "Autonomic HR Regulation." Sports Medicine, 46(10).
4. Mark, Gudith & Klocke (2008). "Cost of Interrupted Work." CHI '08, ACM.
5. Leroy (2009). "Attention Residue." Org. Behavior & Human Decision, 109(2).
6. Newport (2016). Deep Work. Grand Central Publishing.
7. González & Mark (2004). "Multi-tasking Craziness." CHI '04, ACM.
8. Karasek (1979). "Job Demands & Mental Strain." Admin. Sci. Quarterly, 24(2).
9. Kivimäki et al. (2012). "Job Strain & CHD." The Lancet, 380(9852).
10. Van Dongen et al. (2003). "Cumulative Cost of Wakefulness." Sleep, 26(2).
11. Pilcher & Huffcutt (1996). "Sleep Deprivation & Performance." Sleep, 19(4).
12. Hafner et al. (2017). "Economic Costs of Sleep." RAND Corp.
13. Killgore et al. (2006). "Sleep & Emotional Intelligence." Sleep Medicine, 7(5).
14. Greer, Goldstein & Walker (2013). "Sleep & Food Desire." Nature Comms., 4.
15. Monk (2005). "Post-Lunch Dip." Clinics in Sports Medicine, 24(2).
Every algorithm improves as more research emerges. If you spot something we missed, we want to hear about it.