When using a treadmill, the digital display shows a simple number representing speed, but this numerical value can feel abstract without context. The number “4” is a common starting setting, yet its physical meaning—how fast the belt is actually moving—is not always clear. Understanding this precise measurement is the first step toward building an effective workout routine. This clarification translates the display into a functional pace that aligns with personal fitness goals.
The Standard Unit of Measurement
The speed displayed as “4” on a treadmill universally refers to 4 miles per hour (MPH) in the United States. This unit is the default setting for most exercise equipment sold in countries using the imperial system. If the treadmill’s console displays “mi/h” next to the number, the speed is definitively 4 MPH. This rate means that if a person were to maintain that pace for a full hour, they would cover a total distance of four miles.
In other parts of the world, the treadmill may be set to Kilometers Per Hour (KPH), which is a significantly different pace. Four KPH is approximately 2.5 MPH, resulting in a much slower, more leisurely walking speed. Always check the console for the unit label (mi/h or km/h) to ensure the workout intensity matches expectations.
Translating Speed 4 into Exercise Effort
The speed of 4 MPH is classified as a “brisk walk” or “power walk” for the average adult. This pace is substantially faster than a casual walking speed, which falls between 2.5 and 3.0 MPH. At four miles per hour, the walking stride requires continuous effort to keep up with the moving belt. Maintaining this speed is enough to elevate the heart rate and engage the cardiovascular system without transitioning into a jog or run.
To gauge the intensity, this pace corresponds to a Rate of Perceived Exertion (RPE) of 4 to 6 on a 10-point scale. An RPE of 1 is resting, and 10 is maximum effort. At a moderate RPE of 4-6, a person should feel like they are working and experiencing slightly heavier breathing, but still able to hold a conversation. If four MPH feels like a struggle or requires intermittent jogging, the speed is too fast for a steady-state walk.
Adjusting Treadmill Speed for Intensity
Using 4 MPH as a baseline provides a foundation for various workout goals. To increase cardiovascular challenge, the next progression is moving toward a light jog or slow run, achieved by increasing the speed to 5 or 6 MPH. Speeds in this range cross the threshold from power walking into light aerobic activity. This adjustment raises the heart rate further, making the workout more efficient for improving cardiorespiratory fitness.
An alternative way to intensify the 4 MPH pace is to add an incline to the treadmill. Maintaining 4 MPH while increasing the incline simulates walking uphill, which increases the engagement of the leg and glute muscles. This modification builds strength and endurance while keeping the impact low. If 4 MPH feels too easy, increase the speed or incline; if it causes strain, slightly decrease the pace to ensure a sustainable and productive workout.