How to Prevent Blisters When Hiking: Boots, Socks, and Lacing

Day two of the trip, a little after lunch. A slight tingle at your heel, no big deal, you’ll check it at the next break. By the next break, the blister’s there, and the rest of the miles get counted one step at a time. Blisters are the most common hassle in hiking, and one of the easiest to avoid, as long as you deal with them before you hit the trail.

A blister comes from repeated rubbing, and heat and moisture help it form [1]. So prevention comes down to four moves: boots in the right size and already broken in, socks that stay dry, protection on vulnerable spots, and a stop as soon as your skin starts to heat up. This guide expands on that part of the “Gear up and pack your backpack” step in our guide to planning a hike, with what the studies actually measured, and in whom.

Why a blister forms

France’s national health insurance, the Assurance maladie, defines a blister as a lifting of the epidermis, the outer layer of the skin, forming a pocket filled with clear fluid. Under repeated rubbing, the epidermis reddens, then separates from the dermis; the blister then protects the wound underneath. Heat and moisture, heavy sweating for example, encourage it to form [1].

US Army researchers, whose recruits march a lot under heavy loads, laid out the mechanics in a review published in 1995. The greater the friction force, the fewer rubs it takes for a blister to appear. Damp skin rubs more; very dry or very wet skin, less. The sole of the foot, with its thick, snugly held outer layer, is among the most exposed areas, and sustained effort or a heavy load increase the risk [2].

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How your foot presses down matters too. In a small 2010 study of 33 people, those prone to blisters had higher pressures and shear stressesForces that pull the skin parallel to its surface, like a hand sliding across a table and dragging the tablecloth along. under the sole than the others [3]. And history counts for a lot: among 533 runners surveyed after trail races in France in 2021, those who’d had blisters before were much more likely to have them at the finish [4]. If you get them often, this guide is doubly for you.

Boots in the right size, already broken in

Your first line of defense is the boot. The Assurance maladie calls for footwear suited to the shape of your foot, advises against wearing a new pair for too long, and suggests regularly checking the inside by hand for a broken seam or torn leather [5]. The French Hiking Federation, the FFRandonnée, calls fit the most important point of all [6].

The federation’s physician, Dr. Catherine Kabani, explains the sizing trap: if the boot is too big, your foot moves and rubs, with blisters at the front of the foot on descents and at the back on climbs. And don’t count on breaking in a boot that bothers you: as she sees it, the boot isn’t going to adapt to your foot [7].

For the rest, trying boots on in the afternoon, picking a category to match the terrain, and breaking them in before the big trip, see our guide to hiking boots. One more thing, which may annoy high-top loyalists: according to Dr. Kabani, boot height makes no difference to your risk of blisters [7].

Socks: what the studies say

This is where the trailhead folklore lives. Studies do exist, but they’re rare, often military, or done on runners. Here’s what they measured.

Cotton vs. acrylic, first. In 1990, a double-blind study had 35 distance runners run in two socks identical in every way except the fiber: the 100% acrylic socks led to fewer blisters, and smaller ones, than the 100% cotton socks [9]. Dr. Kabani, for her part, advises against thick cotton socks of the “tennis” type, which encourage sweating, as synthetic materials also do in her view; she prefers lisle cotton in summer, a very fine cotton, fine wool, or breathable technical fabrics [7].

Moisture, above all. For hikers, the material seems to matter less than the water. In 2022, Spanish researchers examined 203 walkers on the Camino de Santiago’s Camino Francés, the pilgrimage route across northern Spain, after an average of about 155 miles (250 km) on foot: 68.5% had blisters. The share of natural or synthetic fibers made no difference, but walking in wet socks multiplied the risk by 1.94. The authors recommend changing socks during long stages [10]. If you’re headed for the Camino de Santiago, a spare pair weighs less than a blister.

Two pairs or two layers?

Double layers have their fans. Among 357 Marine Corps recruits in 1996, a thick, dense wool and polypropylene sock worn over a thin polyester liner brought blisters down to 40% of recruits, compared with 69% for the standard military sock. The liner alone, slipped under the standard sock, didn’t reduce the number of blisters (77%), only the cases serious enough to need treatment [11]. So it was the combination that did the job, not the second layer by itself. So-called anti-blister socks, with a double knit, rest on a similar idea: the two layers rub against each other instead of against your skin, Dr. Kabani explains [7]. The American Academy of Dermatology, for its part, recommends nylon or moisture-wicking socks, and suggests trying two pairs if one pair doesn’t help [16].

A systematic review published in 2017 sorted through the evidence: of 11 studies included on socks, antiperspirants, and barriers, only 2 earned moderate confidence. Good-quality evidence is lacking, the authors conclude, and only paper tape may be effective [17]. My take: hiking socks that fit you, suited to the activity as the Assurance maladie recommends [5], and above all a dry spare pair in your pack.

Lacing: locking your heel in place

A heel that slides up and down in the boot with every step is a blister in the making. Scarpa, which makes hiking boots, says heel blisters can come from a boot that holds the heel poorly, and suggests adjusting your lacing, starting from a boot in the right size [18]. Its simplest fix: a surgeon’s knotA simple knot with one extra turn: it holds the tension without slipping. at the base of the ankle, before you lace the top. The most secure option, the heel lock, takes four steps [18].

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Scarpa presents it as a way to lace tightly while spreading the pressure instead of concentrating it under a knot, with one downside: it takes slightly longer laces. Another of the brand’s variations, lacing to the top and then back down, can actually create a pressure point on the ankle [18]. Practice at home, not at the trailhead.

Dry feet, protected skin, short nails

Keep your feet dry. Blisters develop more easily on damp skin, the Assurance maladie points out, and it advises changing socks twice a day if you sweat a lot [5]. At the lunch break, taking your boots off for a few minutes and pulling on the spare pair costs you nothing.

Antiperspirant and powder: mixed results. Among cadets at the US Military Academy at West Point in 1998, a 20% aluminum chloride solution applied on at least three evenings before a 13-mile (21 km) march cut blisters from 48% to 21%, in 269 people; but 57% of users got skin irritation, compared with 6% on the placebo [12]. Another antiperspirant, with added emollients, made no difference in 23 men walking in the heat with 46 lb (21 kg) on their backs [13], and the 1995 review found no effect from drying powders [2], even though the AAD suggests powder or petroleum jelly on problem areas to reduce friction [16]. If you’re tempted, ask a pharmacist well before your trip.

Prep your skin. Dr. Kabani advises massaging your feet for several days before the hike with a suitable product, to soften and moisturize the skin [7]. The 1995 military review also notes that repeated low-intensity rubbing makes the epidermis thicker, which may reduce the risk [2]: one more reason to log a few hours of walking before the big trip.

Trim your toenails. The Assurance maladie advises cutting them straight across, leaving only 0.08 to 0.12 in (2 to 3 mm) beyond the toe, to avoid small injuries and ingrown toenails [8]. A long nail jamming into the end of your boot on every downhill step is nobody’s idea of fun.

On the trail: stop at the first hot spot

The rule fits in one sentence: stop as soon as it starts to burn. At that hot spotAn area of skin that reddens and burns from rubbing: the first stage of a blister., the FFRandonnée says to act as early as possible, with a bandage, at the first burning sensation [6]; Dr. Kabani sees it as the first stage of a blister, the redness stage [7]. The AAD likewise says to stop your activity right away if you feel pain or discomfort, or if your skin turns red [16]. Waiting for the next break often means missing your window.

The first days count double, at least among the ultramarathon runners studied: in the two paper tape studies, 89% and then 80% of blisters had appeared by day 2, or by the end of stage 2 [14, 15]. On a backpacking trip, keep your bandages within reach from the first morning.

At the first sign of heat, in this order:

1. stop and take your boot off, even if the group is moving on in five minutes;
2. dry your skin and, if your socks are wet, change them [10];
3. put a soft bandage or moleskin on the area that’s turning red [16];
4. run your hand around the inside of the boot: a small pebble, a broken seam, or torn leather is enough to hurt you [8];
5. relace, holding your heel more firmly if that’s what is rubbing [18].

Bandages belong in the first-aid kit on our day hike packing list; add a spare pair of socks.

You’ve got a blister: basic care

Despite your best efforts, the blister’s there. The steps below come from the American Academy of Dermatology, which says to be patient and try to leave a blister alone; what to do depends on how it looks [16].

• Intact: cover it loosely with a bandage, bringing in the sides so the middle is slightly raised. On a pressure area, such as the bottom of your foot, cut padding into a donut shape, place it around the blister, then cover both with a bandage.
• Large and very painful: the AAD advises against popping or draining a blister, which could lead to infection, but says it may be necessary to drain one to ease the discomfort. Sterilize a small needle with rubbing alcohol and carefully pierce one edge of the blister to let some of the fluid drain.
• Drained: wash the area with soap and water and apply petroleum jelly. Don’t remove the roof of the blister, which protects the raw skin underneath as it heals, and keep the area clean and covered.

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Don’t go back to the activity that caused the blister until it has healed; most blisters heal on their own in one to two weeks, according to the AAD [16]. MedlinePlus, from the National Library of Medicine, says the same about draining: normally you don’t want to, because of the risk of infection, but you can if a blister is large, painful, or looks like it will pop on its own [20]. Dr. Kabani also recommends a colloid, or hydrocolloid, dressing [7].

When it comes down to it, a blister is won or lost before you leave home: boots in your size and already broken in, dry socks and a spare pair, a few bandages in the first-aid kit. The smart move after that is to stop as soon as it starts to burn, even when the summit is just twenty minutes away. To dress the rest of you, follow the three-layer system, and for everything else in your prep, the steps in our guide to planning a hike.

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In about a minute, REI explains why blisters form, how to prevent them and what to do when one appears.

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Guillaume Hoarau

Camping, backpacking, bushcraft and hiking

Guillaume Hoarau writes for Outfarer about camping, backpacking, bushcraft, and hiking. A survival-skills buff and a collector of vintage field manuals, he loves clear explanations, lists that actually help and other people’s stories, which he tells well.

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