Hundreds of runners put their heart into a race to raise thousands to combat a deadly disease.
Generous runners and walkers made the most of the spring-like weather on Sunday to tackle a five and 10k course around Knebworth Park in aid of the British Heart Foundation.
Participants of all ages warmed up to the sounds of a rock choir before the starting gun sent them on their way.
The organisers of the event, now in its sixth year, estimate the run will raise around �30,000 to tackle heart disease. Click the gallery on the right to see the runners in action.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here