Quick Answer: Pressure sores develop when sustained pressure on bony prominences restricts blood flow. Memory foam, latex, and alternating pressure mattresses redistribute weight to reduce this risk. Medium to medium-soft firmness works best. A quality mattress extends safe repositioning intervals but does not replace the need for regular turning in immobile patients.
7 min read
How Pressure Sores Form
Pressure injuries (also called pressure sores, pressure ulcers, or decubitus ulcers) develop when sustained pressure on the skin compresses the underlying blood vessels, cutting off blood supply to the tissue. Without blood flow, tissue dies. The areas most vulnerable are bony prominences where skin and tissue are thin: the sacrum (tailbone), heels, hips, shoulder blades, and back of the head.
The Science of Interface Pressure
Normal capillary blood pressure is approximately 32 mmHg. When external pressure exceeds this threshold for sustained periods, blood flow is occluded and tissue begins to break down. Research published in the journal Wound Repair and Regeneration has shown that pressure redistribution surfaces that keep interface pressure below 32 mmHg at bony prominences significantly reduce pressure injury incidence. This is why mattress choice matters so critically for immobile or limited-mobility individuals.
Risk factors include immobility (the primary risk factor), malnutrition, incontinence (moisture weakens skin), reduced sensation (neuropathy, spinal cord injury), and age (skin becomes thinner and more fragile). Healthy people avoid pressure injuries because they unconsciously shift position during sleep, typically 20-40 times per night. People who cannot shift, due to paralysis, sedation, or extreme weakness, are at risk.
Mattress Types for Pressure Prevention
Memory Foam
Conforms to body contours, distributing weight across a larger surface area and reducing peak pressure at bony prominences. Higher-density memory foam (4+ lb/ft3) provides better sustained redistribution. Memory foam is the most accessible pressure-relieving material for home use and is available in consumer mattresses at a wide range of price points. The drawback is heat retention, which can be problematic for patients prone to sweating.
Natural Latex
Provides pressure redistribution with better responsiveness than memory foam. When the patient moves, latex springs back immediately, making it easier for caregivers to reposition. Talalay latex is softer and more conforming than Dunlop. Latex is also naturally antimicrobial and hypoallergenic, which matters in a caregiving context where infection risk is elevated.
Alternating Pressure Mattress (Medical-Grade)
Uses electrically powered air cells that cyclically inflate and deflate on a timer, periodically shifting which parts of the body bear weight. This is the gold standard for high-risk patients (Stage 3-4 pressure injuries or those completely immobile). These are medical devices, typically rented or covered through provincial assistive device programs. They are not consumer mattresses.
Hybrid Mattresses
Combining memory foam or latex comfort layers with an innerspring support core, hybrid mattresses offer good pressure relief with better edge support and airflow than all-foam models. For seniors who are mobile but spend significant time in bed, a quality hybrid is often the best balance of pressure relief and practical usability.
Choosing the Right Firmness
Firmness directly affects interface pressure. Too firm, and pressure concentrates at contact points. Too soft, and the body sinks deeply, creating "hammocking" that makes repositioning difficult and can cause shear forces that damage skin.
Firmness Guidelines by Situation
- Mobile seniors (can reposition independently): Medium to medium-firm. Good support with adequate pressure relief.
- Limited mobility (needs assistance turning): Medium to medium-soft. Greater conforming reduces pressure at bony points.
- Bedridden / high risk: Medical-grade alternating pressure surface prescribed by OT. Consumer mattresses are not sufficient for Stage 3-4 prevention.
- Post-surgical recovery: Medium. Enough support for getting in and out of bed independently, with pressure relief for the healing area.
Home Mattress vs Medical-Grade Surface
This is an important distinction. A quality consumer mattress (memory foam, latex, or hybrid) provides meaningful pressure redistribution for people who are at moderate risk, mobile enough to shift position, and spending normal sleep hours in bed.
For patients who are bedridden, immobile, or have existing Stage 2+ pressure injuries, a consumer mattress is not adequate. They need a medical-grade pressure redistribution surface, typically an alternating pressure mattress overlay or a specialized therapeutic mattress. These are prescribed by physicians or occupational therapists and may be partially covered by the Ontario Assistive Devices Program (ADP).
If you are caring for a family member at home and are unsure which category they fall into, consult their physician or an occupational therapist. The right surface can mean the difference between prevention and a wound that takes months to heal.
Practical Caregiver Tips
- Reposition every 2 hours: Even with a quality mattress, immobile patients need regular turning. Use a draw sheet to reduce friction during repositioning.
- Check skin daily: Look for redness that does not blanch (turn white) when pressed. Non-blanchable redness is an early sign of tissue damage.
- Keep skin dry: Use a waterproof mattress protector to manage incontinence. Moisture weakens skin and accelerates breakdown.
- Nutrition matters: Adequate protein intake supports skin integrity and wound healing. Consult a dietitian if the patient is eating poorly.
- Elevate heels: Heels are a common pressure injury site. Use pillows to float the heels off the mattress surface entirely.
- Mattress topper as interim: A 3-4 inch memory foam topper over an existing mattress provides immediate pressure reduction while you evaluate longer-term options.
Home Care Support in the Brantford Area
If you are caring for a senior or recovering family member at home in Brantford, we can help with the mattress side of the equation. At Mattress Miracle, we carry memory foam, latex, and hybrid mattresses that provide meaningful pressure redistribution. We also carry lift chairs and adjustable bases that complement a pressure relief mattress. For medical-grade alternating pressure surfaces, ask your family doctor for a referral to an occupational therapist who can assess eligibility for the Ontario ADP. Call us at (519) 770-0001 to discuss what we can help with.
Medical Disclaimer: This article is for informational purposes and does not constitute medical advice. Pressure injury prevention and treatment should be guided by a qualified healthcare professional, particularly for patients who are immobile or have existing wounds.
Frequently Asked Questions
What type of mattress prevents pressure sores?
Memory foam, latex, and alternating pressure mattresses redistribute body weight to reduce concentrated pressure at bony prominences. For home use, quality memory foam or hybrid mattresses with medium to medium-soft comfort layers provide meaningful relief.
What mattress firmness prevents pressure sores?
Medium to medium-soft. Too firm concentrates pressure at contact points. Too soft makes repositioning difficult and creates shear forces. The ideal firmness allows shoulders and hips to sink while keeping the torso supported.
Can a mattress topper help prevent pressure sores?
Yes. A 3-4 inch high-density memory foam topper significantly reduces interface pressure. It is the most cost-effective first intervention for home caregivers.
How often should a bedridden person be repositioned?
Every 2 hours per National Pressure Injury Advisory Panel guidelines. A quality mattress extends the safe interval but does not eliminate the need for repositioning in completely immobile patients.
Does OHIP cover pressure relief mattresses in Ontario?
The Ontario Assistive Devices Program (ADP) may cover medical-grade alternating pressure surfaces when prescribed by a physician or OT. Consumer mattresses are not typically covered. Contact OHIP or your local CCAC for eligibility details.
What is a pressure sore pillow?
A pressure sore pillow (also called a positioning pillow or pressure relief cushion) is designed to redistribute weight away from vulnerable bony prominences - heels, sacrum, and hips - during extended periods of bed rest. Medical-grade pressure relief pillows use viscoelastic foam or air-cell technology that conforms to the body without creating localized high-pressure zones. Health Canada recommends these products for bedridden individuals in consultation with a healthcare professional.
Caring for Someone at Home? We Can Help.
We carry pressure-relieving mattresses, adjustable bases, and lift chairs at our Brantford showroom. Come in and tell us about your situation. We will give you honest advice about what a home mattress can and cannot do.
441 1/2 West Street, Brantford, Ontario
Call 519-770-0001