What Causes Plantar Fasciitis to Flare Up?
If you’ve dealt with plantar fasciitis, you know how disruptive it can be. It often presents as a sharp, stabbing pain in the heel—particularly noticeable with the first steps in the morning or after periods of rest. While symptoms may improve with rest, treatment, or changes in footwear, the condition can flare up unexpectedly, even after a period of relief. Understanding what triggers these flare-ups begins with a closer look at the underlying anatomy and mechanics of the condition.
What is plantar fasciitis?
Plantar fasciitis is one of the most common causes of heel pain. It occurs when the plantar fascia—a thick band of connective tissue that spans the bottom of the foot from the heel bone (calcaneus) to the toes—becomes inflamed due to repetitive stress or overuse.
The primary function of the plantar fascia is to support the arch of the foot and absorb the shock generated during activities like walking, running, or standing. When the fascia is subjected to repeated tension or excessive loading—whether from high-impact activities, prolonged standing, or inadequate footwear—tiny microtears can develop in the tissue. Over time, these microtears can lead to inflammation, pain, and stiffness, particularly near the heel where the fascia attaches to the bone.
One hallmark symptom is morning heel pain, which occurs because the fascia tightens during periods of inactivity. Upon standing and taking the first steps of the day, the tissue is abruptly stretched, triggering discomfort. Similar pain may occur after sitting for long periods or after intense physical activity.
Why does plantar fasciitis flare up?
Plantar fasciitis is often a result of repetitive stress on the plantar fascia — the thick band of tissue that runs along the bottom of your foot. While many people manage symptoms with rest and proper care, flare-ups are common and usually tied to specific triggers. Here’s a closer look at what might be causing your discomfort:
Inadequate footwear support
The shoes you wear play a major role in either preventing or aggravating plantar fasciitis. Footwear that lacks proper arch support, cushioning, or has worn-out soles can significantly increase stress on the plantar fascia.
Common culprits include:
• Flat-soled shoes such as ballet flats or flip-flops
• Worn-down running shoes
• Walking barefoot on hard surfaces (e.g., tile or hardwood)
What to do: Choose shoes with structured arch support, cushioned heels, and a slight heel-to-toe drop. Orthotic inserts — either custom or over the counter — can also help redistribute pressure and improve alignment, especially if you’re on your feet for extended periods.
Increase in physical activity
One of the most common reasons for a plantar fasciitis flare-up is doing too much, too soon. If you significantly ramp up your walking, running, or other physical activity without giving your body time to adapt, the plantar fascia absorbs excessive strain.
This is particularly problematic if:• You’ve recently changed your exercise routine
• You’re returning to activity after time off
• You haven’t allowed adequate rest between workouts
Without proper conditioning, the tissue becomes overloaded, leading to micro-tears and inflammation.
What to do: Stick to the “10% rule” — increase your activity level gradually, no more than 10% per week. Allow for rest and recovery, and consider alternating high-impact workouts with low-impact activities like swimming, cycling, or yoga to reduce stress on the foot.
Prolonged standing on hard surfaces
Spending long hours on your feet—particularly on hard surfaces is a common trigger for plantar fasciitis flare-ups. Occupations that require extended standing, such as teaching, healthcare, retail, or warehouse work, place continuous stress on the plantar fascia throughout the day.
When you’re standing still for prolonged periods, especially without adequate arch or heel support, the plantar fascia is put under sustained tension. Unlike walking or movement, where pressure is more evenly distributed across different parts of the foot, standing in place concentrates the load on specific areas—most often the heel and arch. This leads to compression and fatigue of the fascia, which can result in inflammation and microtears over time.
To reduce the impact of prolonged standing, supportive footwear with ample cushioning and arch support is essential. Orthotic inserts, anti-fatigue floor mats, and scheduled movement breaks can also help redistribute pressure and give the plantar fascia a chance to recover throughout the day.
Weight gain
Gaining weight can significantly increase the mechanical load placed on your feet. Since the plantar fascia plays a key role in supporting your body weight and maintaining the arch of your foot, any additional weight amplifies the stress on this tissue with every step you take. This added pressure increases the risk of microtears in the fascia, especially around the heel where the tissue anchors to the bone. Over time, repeated strain without sufficient recovery can lead to inflammation and pain—a hallmark of plantar fasciitis.
Weight gain can also alter your biomechanics. Extra weight may shift your centre of gravity, affecting your gait and posture. These subtle changes can place uneven stress on the feet, ankles, knees, and hips, further contributing to discomfort and increasing the likelihood of a flare-up. It’s also worth noting that people with a higher body mass index (BMI) may experience a slower recovery from plantar fasciitis if the increased mechanical load is not addressed alongside treatment.
Cold weather
Believe it or not, colder weather can make plantar fasciitis worse — especially if you’re skipping warm-ups before heading outside. Cold temperatures tend to make muscles and connective tissues stiffer and less flexible, which means your plantar fascia is more prone to injury.
Tip: Before heading out for a walk or run in the cold, take a few minutes to warm up your feet and legs with gentle stretches. And even if you’re just staying indoors, choose warm, supportive footwear with cushioning.
