How to Start Running After Walking
Use short run intervals, easy effort, and gradual repetition instead of making the first run a verdict.
Keep the walking habit and insert small, relaxed running intervals. Finish before form and breathing fall apart, then repeat the same workload several times before increasing it.
Keep the reliable part
Your walking routine already proves a time, route, and cue can work. Preserve those pieces. The new variable is only a short amount of running.
Run slower than your excitement
The first interval should feel controlled enough that you could have done more. Speed is not the graduation requirement; repeatability is.
Use pain as information
Normal effort and unfamiliar muscle work are not the same as sharp or worsening pain. Stop when pain changes your movement and seek appropriate professional advice when it persists.
Reference point: Current public-health guidance says some activity is better than none, adults can combine moderate activity such as brisk walking with vigorous activity such as running, and inactive people should start small and build gradually. See CDC adult activity guidance and the NHS Couch to 5K introduction.