The truth about burning calories and why your workout isn’t the whole story
Fitness trackers flash the number the second you finish a workout, and most of us treat it as the scoreboard for whether a session was "worth it." But few people stop to ask what a calorie actually is, why we've built an entire culture around this one number, or why the number quietly shrinks the fitter you get.
What a calorie actually is
A calorie is simply a unit of energy — specifically, the energy needed to raise the temperature of one gram of water by one degree Celsius. It has nothing inherently to do with fat, willpower, or moral virtue. When we say you "burned 400 calories," we mean your body converted roughly that much stored chemical energy (from food, fat, or glycogen) into heat and mechanical work to keep you moving, breathing, and thinking during that Chisel N Stride group class or personal training session.
Why we're obsessed with the number
The calorie became fitness culture's favorite metric for a simple reason: it's the one thing wearables and machines can spit out in real time, and it feels like proof. Steps are vague, "how you feel" is unmeasurable, but a number on a screen feels objective and comparable — Monday's circuit strength class vs. Frida’s stride & stretch class. It plugs neatly into the "calories in, calories out" model of weight management, which is true in principle but wildly oversimplified in practice, since those on-screen estimates are frequently off by 20–40%, especially on wrist-worn devices.
The obsession also has a psychological pull: a single number gives instant feedback and a sense of control in a process (fitness, body composition) that's actually slow and multifactorial.
What actually influences how many calories you burn
Total energy expenditure during exercise is shaped by far more than the workout itself:
Body mass — heavier bodies require more energy to move, so the same run burns more calories for a 90kg person than a 60kg person.
Muscle mass — muscle is metabolically active tissue; more of it raises your resting energy needs and the energy cost of moving.
Exercise intensity and duration — higher heart rate and longer duration both raise total burn, though the relationship isn't perfectly linear.
Exercise efficiency — how mechanically "clean" your movement pattern is. A novice runner wastes energy on excess vertical bounce and poor arm-leg coordination; an efficient runner converts more energy directly into forward motion.
Fitness level — a well-conditioned cardiovascular and muscular system requires less energy to produce the same output.
Environmental factors — heat, humidity, altitude, and terrain all add metabolic cost.
Individual variation — genetics, hormones (especially thyroid function), age, and even gut microbiome composition all shift energy expenditure between two people doing an identical session.
Why getting fitter means burning less for the same workout
This is the part that surprises — and sometimes frustrates — people: as you get fitter, your body becomes more efficient, and efficiency is the enemy of calorie burn. Think of it like an engine. An untrained body doing a 5km run is like a car with poor fuel efficiency — it wastes energy on inefficient movement patterns, recruits more muscle fibres than necessary, and relies heavily on less efficient energy systems. A trained body doing the exact same 5km run has improved its running economy: better mitochondrial density, stronger tendons that store and return elastic energy, smoother neuromuscular coordination, and a cardiovascular system that delivers oxygen with less effort. The result is that trained body completing the same distance at the same pace using measurably less energy.
This is also why your heart rate at a given pace or resistance level drops as you get fitter — a lower heart rate for the same workload is a fitness marker, but a lower heart rate also generally correlates with lower calorie expenditure at submaximal effort. You're not "getting worse" at burning calories; you're getting better at the exercise itself, which by definition costs less energy.
The bit most corporate professionals miss: it's not just about the session
Here's where this gets particularly relevant if your day is spent mostly at a desk. A single training session at Chisel N Stride — even an intense one like Chisel N Hike & Stride or HIIT and Strength at the Springboard — is a small window in a 24-hour day. If you train hard for 45 minutes and then sit for the other 15+ waking hours, that one session is fighting an uphill battle against what's called NEAT: Non-Exercise Activity Thermogenesis. NEAT covers all the energy you burn from movement that isn't formal exercise — walking to a meeting, taking the stairs, standing to talk to a colleague, pacing on a call, even fidgeting. For most office-based professionals, NEAT actually accounts for a larger share of daily energy expenditure than the workout itself.
This matters because it's easy to fall into the trap of thinking one good class "earns" the right to sit still for the rest of the day. Physiologically, it doesn't work that way. A body that sits for 9-10 hours and trains for 1 burns meaningfully less across the day than a body that sits less and moves consistently, even if the workout itself is identical.
So the practical takeaway for anyone with a desk-based job: don't rely on your Chisel N Stride session to do all the work. Build movement into the parts of the day around it:
Get up every 45-60 minutes — even a two-minute walk to refill your water bottle interrupts prolonged sitting and adds up across a workday
Take the stairs over the lift
Walk during calls that don't need a screen, instead of taking them seated
If you have standing desks use them
Go for a walk at lunchtime — even 15-20 minutes outside the office breaks up hours of sitting and is one of the highest-leverage habits for daily energy expenditure.
If you’ve got a closed office - do wall exercises as you’ve been shown in a personal training session or some movements from a Chisel N Stride group class
None of these need to feel like "exercise" — that's the point. They're low-effort, low-friction ways of staying out of the chair, and collectively they can outweigh the impact of the training session itself.
What this means for you
If calorie burn is your only metric, plateaus will feel like failure. But the smarter frame is this: calories burned in a single session is a poor long-term indicator of progress. The better markers are performance (are you lifting heavier, running faster, hiking longer), recovery, strength, mobility, and how you feel day to day. If your goal is still to increase energy expenditure as you get fitter, the solution isn't more of the same in the studio — it's progressive overload in your training, and less time in the chair everywhere else.
The number on your wrist is a rough estimate of energy and not a report card. Train for capability, move throughout your day, and the calories will follow.