Happy Thursday, Zapien.

Forever,
Karol, Martin, Simon & Andy

By Rob ter Horst

Rob may have the most-scanned brain on the planet, and he has tested more wearables against medical-grade equipment than almost anyone alive.

So when he says most people should track less and stop trusting the scores their device invents, it is worth listening.

In this interview he settles the question the community asks most, Oura versus Whoop versus Apple Watch, and names the budget tracker that beat a premium favourite on his own body.

He reveals which metrics are genuinely accurate, which fall apart the moment you test them, and why your nightly sleep score means less than you think.

He also shares the two or three numbers actually worth watching, the point where tracking quietly starts harming your health, and whether a continuous glucose monitor earns its price or is just expensive curiosity.

When Rob ter Horst is asked which numbers a busy person should watch, one of his answers needs no device at all: you can gauge whether your easy cardio is truly easy by whether you can still hold a conversation.

Sports science backs this up. The "talk test" measures your speech comfort during exercise, and the point where talking first becomes difficult tracks your ventilatory threshold, the boundary between comfortable aerobic work and harder effort, closely enough to guide how you train.

A randomised trial later showed the test can be used on its own to control intensity, with the still-talking stage landing squarely in the range used for recovery and long, easy sessions. For anyone coming back from overtraining, illness, or too many hard weeks, keeping most sessions at a talkable pace is one of the simplest ways to rebuild your aerobic base without digging the hole deeper.

This week's interview makes the case that most people track too much and trust scores that were never reliable. So instead of another readiness number, we built a prompt that does what no wearable will: it tells you what to stop tracking, and which handful of signals are genuinely worth your attention.

Arnold built the most recognisable physique in sporting history before becoming a global film star and a two-term Governor of California. Decades on, he remains a leading advocate for accessible, lifelong fitness, championing the idea that staying strong and healthy is a project for every age, not just the young.

Morning.

Arnold is up early and starts the day with a strong espresso, then rides his bike the two-plus km from Santa Monica to Gold's Gym in Venice, the same gym from his bodybuilding years, getting his first cardio in before he even arrives. His weight training now runs on a two-day rotation, one day for shoulders and arms, the next for chest, back, and calves, with abs worked every session through sit-ups and crunches. The weights are lighter than in his prime and the focus has shifted to form, control, and full range of motion for joint health and longevity, with sessions lasting around thirty to forty-five minutes. After training he typically refuels with oatmeal and Greek yogurt, or Greek yogurt with granola, one of his go-to high-protein, meat-free breakfasts.

Afternoon.

He eats a roughly seventy percent plant-based diet, a deliberate shift he made for heart health and the environment. He is open that meat now makes up only about twenty percent of his protein, with staples like eggs, salmon, and chicken increasingly giving way to veggie burgers, lentils, and beans, and he argues plant protein can be made as effective as whey. Lunch is almost always a salad, sometimes alongside a plant-based burger or a portion of salmon or chicken. He keeps things simple and repeatable rather than chasing complicated meal plans.

Health Disclaimer

New Zapiens’ products and services are not intended to substitute for professional medical guidance. Our content and media offerings do not aim to diagnose, cure, or address any medical issues.