Rucking and Weighted Vests: What the Research Actually Backs Up
Weighted vest sales jumped more than 50% in a single year, and "rucking" — walking with a loaded pack, borrowed straight from military training — has become one of the most talked-about low-effort workouts around. Some of the marketing claims are exaggerated. Some of the underlying science is genuinely solid. Here's what peer-reviewed research says about calorie burn, bone density, and who this actually makes sense for, including a 2025 clinical trial that complicated one of the field's favorite claims.
Rucking borrows its name and its basic method from military load-carriage training — but most of the people trying it now are carrying a fraction of what soldiers do.
No, Rucking Doesn't Burn 2-3x More Calories
The most repeated claim about rucking — that it burns two to three times as many calories as regular walking — traces back to military studies of soldiers carrying 45 to 65-pound packs over long distances. That's not what most people trying rucking are doing. For the loads recreational walkers actually use, generally 5-15% of body weight, fitness researchers who've reviewed the underlying data put the realistic increase at 10-20% above unloaded walking — meaningful, but nowhere near the number that gets thrown around in marketing.
Where the load-carriage research is more interesting is oxygen demand: adding 15-30% of body mass to a walk can roughly double VO2 consumption compared to walking unloaded, according to a review of the load-carriage literature. That's specifically useful for people trying to reach Zone 2 cardio intensity without breaking into a run — rucking can get you there through added resistance rather than added speed.
A 2025 Trial Complicated the "Vests Build Bone" Story
Bone density claims for weighted-vest walking rest on older, smaller trials — and a 2025 study found the effect doesn't hold up as cleanly as the marketing suggests.
The bone-health case for weighted vests rests heavily on a study by Snow and colleagues, published in 2000, which followed 18 postmenopausal women for five years. The group doing weighted-vest exercise combined with jumping preserved hip bone mineral density far better than the control group — controls lost 3.8% over five years, while the exercise group lost less than 1%. That result has been cited for two decades as evidence that loaded walking protects bone.
A 2025 trial called INVEST, published in JAMA Network Open with 150 participants, complicated that picture. It specifically tested weighted-vest use during intentional dietary weight loss in older adults, and found the vests did not prevent the bone loss that typically comes with losing weight. The takeaway isn't that vests are useless for bone health — it's that the effect seen in the original small trial, paired with jumping and outside a weight-loss context, doesn't automatically generalize to every situation people are now using vests for.
Rucking Pack or Weighted Vest — and How Much Weight
- Starting at 5-10% of body weight, adding gradually over weeks
- Weighted vests for shorter, indoor, or treadmill sessions
- Rucking packs with a hip belt for longer outdoor distances
- Pairing the walk with basic resistance work — squats, rows, lunges
- Anyone with existing neck or back pain
- Pregnant women, per Harvard Health guidance
- Anyone jumping straight to loads above 15-20% of body weight
- Anyone with joint issues who hasn't cleared it with a doctor first
A loose pack that shifts around, or a poorly fitted vest that bounces, changes your posture and increases injury risk more than the added weight itself does — fit matters as much as load. Most guidance converges on the same starting point: roughly 5-10% of body weight for the first couple of weeks, working up toward 10% as a reasonable long-term target for most people, per Harvard Health's recommendation.
Is It Worth Adding to Your Routine?
Yes, with realistic expectations about what it does and doesn't do.
Weighted walking is a low-skill, genuinely evidence-supported way to add intensity to something you're probably already doing. Where it falls short is the marketing around it — the calorie-burn multipliers are inflated, and the bone-density benefits are less settled than older, smaller studies suggested. Used as one part of a broader fitness routine, with a sensible starting weight, it's a solid addition. Used as a substitute for actual resistance training, it isn't.
Frequently Asked Questions
Does rucking really burn 2-3x more calories than walking?
Not for the loads most people actually use. That figure comes from military studies of soldiers carrying 45-65lb packs over long distances. For recreational loads of 5-15% of body weight, a more realistic estimate is a 10-20% increase in calorie burn over unloaded walking, according to fitness researchers who've reviewed the underlying military data.
Does a weighted vest actually improve bone density?
The evidence is mixed. A 5-year trial by Snow and colleagues found weighted-vest exercise combined with jumping helped preserve hip bone density in postmenopausal women. But a 2025 trial called INVEST, published in JAMA Network Open, found weighted-vest use alone did not prevent bone loss during intentional weight loss in older adults — complicating the simple "vests build bone" narrative.
How much weight should I start with for rucking or a weighted vest?
Most sources recommend starting around 5-10% of body weight for a few weeks before adding more, and Harvard Health specifically suggests staying around 10% of body weight for most people long-term. People with neck or back pain, or who are pregnant, are generally advised to avoid weighted walking altogether.
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