A runner holding Dr. Nice's Sports Hydrogel for Runners in one hand while she dabs one dot of gel on a hot spot on her heel

Hot Spots at Mile 18: What Your Feet Are Telling You

October 27, 2026

Mile 18. Shoe off. One small bottle.

The short answer: A hot spot is the warm, tender, rubbed patch you feel before a blister forms. When one shows up mid-run, stop, take the shoe off and fix what's rubbing: a sock wrinkle, grit or a loose heel. Then a thin layer of Sports Hydrogel for Runners cools and soothes the hot spot and dries into a breathable barrier.

Why Sports Hydrogel for Runners Is the One to Reach For

A hot spot gives you a few miles of warning. Here's why runners keep Dr. Nice's Sports Hydrogel for Runners in the vest pocket for exactly that moment:

It cools and soothes hot spots. It's a water-based hydrogel that cools on contact, right on the patch your sock has been working on for the last hour.
It dries into a thin, breathable barrier. That film cuts friction before it starts, so the same spot isn't taking every stride on bare skin.
It's on in the time it takes to retie a shoe. A pearl-sized amount, spread thin, dries clear in about 30 seconds. Sock up, shoe on, back on the road.
It won't gum up your socks, shoes or tech fabric. It goes on clear and non-greasy, and it doesn't stain.
One bottle covers every friction zone. Heels and toes today. Inner thighs, underarms and nipples the rest of the training block. It soothes blisters and chafe too.
It works on both ends of the run. A thin layer before you lace up, and a cooling layer after the shower.
It fits the kit. One 30 mL (1 fl oz) airless pump rides in a race belt, a vest pocket or a hydration pack.
Five clean ingredients. Water, poloxamer, gluconolactone, sodium benzoate and a minuscule amount of peppermint oil, which gives it a light peppermint scent. Vegan, and made in the USA in an FDA-registered facility.
A pharmacist made it. It was formulated by pharmacist Dr. Frank J. Nice, RPh, DPA, CPHP.

Shop Sports Hydrogel for Runners →

What a Hot Spot Is, and Why It Shows Up at Mile 18

Peak week. The longest run of the cycle. Somewhere around mile 18 the back of your right heel gets warm. It doesn't hurt yet. It's just there, and every stride makes it a little more there.

That's a hot spot: the patch where your shoe or sock has been rubbing the same piece of skin over and over until it turns red, warm and tender. The skin is still whole. It's a warning, and the thing it's warning you about is a blister. The American Academy of Dermatology (AAD) is direct about it: stop your activity if you feel pain or discomfort or your skin turns red, because otherwise you may get a blister.

Why mile 18 and not mile 2? A few reasons stack up late in a long run:

Repetition. MedlinePlus explains that blisters often happen when there's friction, rubbing or pressure, on one spot. A long run is that same rub thousands of times. A review in Current Sports Medicine Reports by Martin D. Hoffman names the number of shear cycles as a factor in blister development, and every stride is another one.
Sweat. Cleveland Clinic foot specialist Georgeanne Botek, DPM, notes that people with sweaty feet are more prone to blisters. Two hours in, your socks aren't dry anymore.
Grit and fit. The same review lists keeping moisture and particles away from the skin, and shoes that fit and are broken in, among its key strategies. A bit of road grit in the sock or a heel that slips in a loose shoe gives friction one more place to work.

A woman on a long autumn training run glances down at her foot on a leaf-covered road

What to Do the Moment You Feel It

1. Stop now, not at the next water stop

The instinct is to finish the loop. The hot spot doesn't care about your loop. The AAD's advice is to stop when the skin turns red, and two minutes on the curb at mile 18 is cheaper than a blister you nurse for the rest of the week.

2. Find what's rubbing

Shoe off, sock down, and look. A wrinkle in the sock, a seam sitting right on the spot, a bit of grit, or a sock that's soaked through. Dr. Botek points out that sock seams rubbing at the wrong angle can cause blisters on their own, which is why so many running socks are made with flat or no seams.

3. Dry it, and swap the sock if you can

Wipe the foot dry. If you carry a spare pair, this is what it's for: Dr. Botek suggests keeping an extra pair handy in case your feet get sweaty and you need a quick change.

4. Cool it and lay down a barrier

The steps above come from those sources. This one is ours. Pump one pearl-sized dot of Sports Hydrogel for Runners onto your fingertip and spread a thin layer over the hot spot. It cools on contact, soothes the warm patch, and dries clear in about 30 seconds into a thin, breathable film between your skin and the sock. Smooth the sock back on with no wrinkles, and lace up.

One pearl-sized dot of clear gel on a fingertip touching a pink hot spot on a runner's heel

5. Retie the shoe

Dr. Botek warns that shoes that are too big or too small encourage extra friction. If your heel has been lifting in the shoe, snug the laces so it sits still. If the shoe is the problem every week, that's a conversation for after the run.

6. Listen to it for the next mile

If the spot settles down, carry on. If it keeps building, the honest move is to shorten the run. One shortened long run won't sink a training block. A blister that keeps you off your feet for a week might. The AAD also suggests adhesive moleskin or another soft bandage, applied securely, for problem areas, so it's worth having a piece in the pocket on long days.

If It's Already a Blister

Sometimes the shoe comes off and the hot spot has already moved on to the next stage. The AAD's advice is to leave it alone and loosely cover it with a bandage, bringing the sides in so the middle is a little raised. On the bottom of the foot, the AAD suggests a donut-shaped pad around it. Dr. Botek's general rule is not to pop a blister as long as it isn't painful.

Our gels are made for intact skin. On a blister that's still closed, a thin layer cools and soothes. If the skin has torn open, keep it clean and covered, and save the gel for the skin around it.

After the Run

Shower, dry your feet well, including between the toes, and take a look at the spot in good light.

This is where the cooling part earns its place. A thin layer of Sports Hydrogel for Runners on the warm patch cools and soothes skin that just did 18 miles of work. The fridge trick: put the bottle in the fridge for about 10 minutes before your shower and the gel turns into a thin liquid for an extra-cool feel, then thickens back up as it warms on your skin.

If it did turn into a blister, the AAD suggests holding off on the activity that caused it until it's gone. That's annoying in peak week. It's less annoying than missing race day.

Before the Next Long Run

The fix for next Saturday is mostly about friction and moisture:

Socks. The AAD recommends nylon or moisture-wicking socks, and if one pair doesn't do it, trying two. Dr. Botek notes that synthetic socks are often preferred over all-cotton, which can trap moisture.
Shoes. MedlinePlus says to make sure your shoes fit properly. Dr. Botek's advice is to break new shoes in slowly, so race-day shoes shouldn't make their debut on an 18-miler.
Dry feet. For sweaty feet, Dr. Botek suggests a drying agent such as cornstarch or talc-free foot powder before you work out.
Mileage. Hoffman's review lists skin adaptation through proper training among its strategies, which is one more reason long runs build up over weeks rather than jumping.
A thin layer before you lace up. Ours: Sports Hydrogel for Runners on your heels, toes and any spot that's talked to you before. It dries into a thin, breathable barrier that cuts friction before it starts.

More from the Sports Care blog: the reality of running-related skin irritation, hydration, friction and peak performance, and, for the trail days, hiking blisters on long hikes.

When to See a Doctor

Sports Hydrogel for Runners is for everyday hot spots, blisters and chafe on intact skin. Based on guidance from MedlinePlus, the AAD and Cleveland Clinic, see a doctor if:

It drains pus, or the skin around it turns red, swollen, warm or very painful
You have a fever
Red or purplish streaks spread from the spot (Cleveland Clinic says to seek emergency care right away)
There's a bad smell
You have several blisters and can't work out what's causing them
You have poor circulation or loss of feeling in your feet: get any blister checked sooner rather than later
It's getting worse instead of better

Frequently Asked Questions

What's the best thing to do for blisters after a run?

Apply Dr. Nice's Sports Hydrogel for Runners. It cools on contact, soothes the blister and dries into a thin, breathable barrier, so you can get back to running. If the blister has torn open, keep it clean and covered, and use the gel on the skin around it.

What should I do when I feel a hot spot while running?

Stop, take the shoe off and find what's rubbing: a sock wrinkle, a seam, grit or a wet sock. Dry the foot, swap the sock if you carry a spare, then spread a thin layer of Dr. Nice's Sports Hydrogel for Runners over the spot. It cools on contact and dries clear in about 30 seconds. Retie the shoe so your heel doesn't lift.

What can I put on my feet before a long run?

Dr. Nice's Sports Hydrogel for Runners. A thin layer on your heels, toes and any spot that's talked to you before dries clear in about 30 seconds into a breathable barrier that cuts friction before it starts. It won't gum up your socks or shoes.

What's good for chafing from running?

Dr. Nice's Sports Hydrogel for Runners. Before the run, a thin layer on the inner thighs, underarms and nipples dries into a breathable barrier that cuts friction. After the shower, it cools and soothes chafe. It's clear and non-greasy, so it won't stain your tech fabric.

What causes hot spots on feet when running?

Friction. Your shoe and sock rub the same patch of skin with every stride, and sweat, grit, a sock wrinkle or a loose heel add to it. On a long run that rubbing adds up, which is why hot spots tend to show up late in the run, not at mile two.

Should I pop a blister from running?

Usually not. The American Academy of Dermatology suggests leaving it alone and loosely covering it with a bandage, with the middle a little raised, or using a donut-shaped pad on the bottom of the foot. Georgeanne Botek, DPM, of Cleveland Clinic says not to pop a blister as long as it isn't painful. On a blister that's still closed, a thin layer of Sports Hydrogel for Runners cools and soothes.

What socks help with blisters when running?

Nylon or moisture-wicking socks, according to the American Academy of Dermatology, and two pairs if one doesn't do it. Georgeanne Botek, DPM, of Cleveland Clinic notes that synthetic socks are often preferred over all-cotton, which can trap moisture, and that seams rubbing at the wrong angle can cause blisters on their own, so look for flat or no seams.

What should I carry on a long run for my feet?

Dr. Nice's Sports Hydrogel for Runners, a spare pair of socks, and a piece of adhesive moleskin or a soft bandage for problem spots. The 30 mL pump rides in a race belt, a vest pocket or a hydration pack.

When should I see a doctor about a blister?

See a doctor if it drains pus, if the skin around it turns red, swollen, warm or very painful, if you have a fever or there's a bad smell, or if you get several blisters and can't work out why. Red or purplish streaks spreading from the spot need emergency care right away (Cleveland Clinic). If you have poor circulation or loss of feeling in your feet, get any blister checked sooner rather than later.

Keep Running

A hot spot at mile 18 isn't a crisis. It's information. Stop, find what's rubbing, fix it, and put a thin layer of Sports Hydrogel for Runners on the warm patch before the sock goes back on. Then finish the run you came out to do.

Whether you're chasing a qualifying time this fall or just trying to get through Saturday's 18 without stopping twice, reach for Dr. Nice's.