Let me be honest about what we're looking at here. A 7.5-day dry fast — no water, no food — is an extreme protocol that most researchers wouldn't endorse, and I'm not going to pretend otherwise. But the blood work Tone Vase shares on day two of his recovery is genuinely fascinating, and it opens a window into something I find deeply compelling: how far metabolic flexibility can stretch before it breaks.
A glucose reading of 48.5 mg/dL would trigger a clinical alarm in any emergency room. Below 70 is hypoglycemia by standard definition. Yet he's functional, coherent, walking around on a Caribbean island planning a barbecue. This is only possible because the body, when forced to adapt over days without water or food, becomes extraordinarily efficient at gluconeogenesis — manufacturing glucose from amino acids and glycerol — while shifting primary fuel consumption toward ketones. The insulin level of 2 confirms it. The pancreas essentially went quiet. The body found another way.
The recovery piece is where things get interesting, and where our knowledge base adds real texture. A 2015 cryotherapy study in the database found that partial-body cold exposure — even without head immersion — produced a 49.1% increase in heart rate variability (RMSSD), a direct marker of parasympathetic nervous system activation. That's the recovery state. That's the signal that your body has shifted from fight-or-flight into rest-and-repair.
Post-fast, the autonomic nervous system is under stress. Glucose is low. Cortisol has likely been elevated for days. The body is in a cautious, depleted state. Introducing deliberate cold exposure at this juncture — carefully, not aggressively — can help tip the nervous system back toward parasympathetic dominance. Heat follows the same logic. Elevated core temperature triggers heat shock proteins, those molecular chaperones that refold damaged proteins and clear cellular debris. After a week of metabolic stress, that housekeeping work matters enormously.
Most sports scientists and metabolic researchers would flag the sleep data as the real concern here — not the blood work. Six hours total, only three restorative. The knowledge base on recovery consistently shows that sleep quality drives adaptation more than almost any active intervention. The soccer recovery paper in our database examines how elite athletes differ in their recovery capacity based on position — and the universal finding is that sleep-deprived athletes don't absorb the benefits of recovery protocols the way rested ones do. The protocol doesn't matter if the foundation is broken.
Tone Vase acknowledges this himself. He knows he should have been in bed earlier. That self-awareness is actually the most important thing in this video.
If you're refeeding after any significant fast — even a 24 or 48-hour intermittent fast, let alone a multi-day protocol — treat the recovery period as its own phase with its own rules. Gentle heat first, before cold. Let your circulation normalize. Let blood glucose stabilize. Don't plunge into ice water when your glucose is at 48. That's a sympathetic nervous system spike your body doesn't need right now. Give it 48 to 72 hours of soft reintroduction — warm food, gentle heat, prioritized sleep — before asking your body to adapt to additional thermal stress.
There's a placebo paper in our cold water immersion research that keeps surfacing in my thinking. It found that post-exercise recovery outcomes were measurably influenced by what participants believed about the intervention — not just what the intervention actually did physiologically. Our beliefs shape our biology, particularly under stress. After seven and a half days of extreme physiological challenge, the ritual of recovery — the intentional meal, the deliberate heat, the mindful cold — carries meaning that compounds the physical effect. You're not just rehydrating. You're signaling to your nervous system that the crisis is over. That signal is real. It has biological weight.
That's what contrast therapy does at its best. It's not just temperature. It's a ritual of return.