Feet sweat a lot because they have many sweat glands and are affected by heat, stress, footwear, or hyperhidrosis.
Why
Feet have about 250,000 sweat glands, more per inch than any other part of the body (about 125,000 per foot).
Causes
- Heat and humidity.
- Shoes and socks that trap moisture.
- Stress and hormones.
- Hyperhidrosis, excessive sweating affecting up to 3 percent of people.
- Medications and some medical conditions.
Smell
Bacteria breaking down sweat create odor.
Tips
- Wash and dry feet well.
- Wear moisture-wicking socks and breathable shoes.
- Use antiperspirant on feet.
- Rotate shoes.
Treatment
Prescription antiperspirants, iontophoresis or Botox.
See a doctor if
Sweating is severe or suddenly begins.
How sweat glands work
The feet have about 250,000 sweat glands, more per square centimeter than any other part of the body, roughly 600 per square centimeter on the soles. They are eccrine glands, and they help regulate temperature, but on the feet they respond more to emotion and activity. Shoes and socks trap moisture and heat, so the sweat has nowhere to evaporate.
Common causes
- Plantar hyperhidrosis: overactive sweat glands without a clear cause, affecting up to 1% to 3% of people, often starting in childhood or the teens and running in families.
- Heat, exercise and tight, non-breathable shoes.
- Stress and anxiety, which trigger palmar and plantar sweating.
- Hormonal changes in puberty, pregnancy and menopause.
- Thyroid overactivity, diabetes with low blood sugar, and some medications.
Why feet smell
Sweat itself has little odor. The smell comes from bacteria, such as Brevibacterium and Micrococcus species, that break down dead skin and sweat into compounds like isovaleric acid and sulfur compounds. Damp socks and shoes provide a perfect growth environment.
Everyday tips
- Wash feet daily with soap and dry fully, especially between toes.
- Wear moisture wicking socks in wool or synthetic blends, and change them once or twice a day.
- Rotate shoes, letting each pair dry for 24 hours.
- Choose leather, canvas or mesh shoes over plastic.
- Use foot powder or an absorbent insole.
- Wash shoes or use antibacterial insoles.
Medical treatments
- Prescription antiperspirants with aluminum chloride (10% to 20%), applied at night.
- Iontophoresis, a device that passes a mild current through water to reduce sweating, with success in most users after several sessions.
- Botulinum toxin injections, which last about 4 to 6 months.
- Oral anticholinergic drugs such as glycopyrrolate, which can cause dry mouth.
- Surgery (sympathectomy) is a last resort, with a risk of compensatory sweating elsewhere.
Athlete’s foot and infections
Constantly damp feet raise the risk of athlete’s foot, a fungal infection causing itching, peeling and cracks. Treat with an over the counter antifungal cream for 2 to 4 weeks.
See a doctor if
Sweating starts suddenly, comes with night sweats or weight loss, affects only one foot, or keeps you from daily activities.
Numbers on foot sweating
Each foot has about 125,000 sweat glands, which together produce up to about a half pint of moisture per day, per the American Podiatric Medical Association. Foot odor comes from bacteria such as Brevibacterium and Micrococcus that break down sweat. Plantar hyperhidrosis affects about 3 percent of people. Tips: rotate shoes every other day so they dry fully, wear moisture-wicking socks, use aluminum chloride antiperspirant at night, and choose leather or breathable fabric shoes. Iontophoresis devices reduce sweating in many patients after repeated sessions.
Based on data from the American Podiatric Medical Association and the International Hyperhidrosis Society
