[Andrew Bollard]

Hi Yvonne, I was in this exact situation 6 months ago when I started training using TftNA/TftUA principles. It’s worth pointing out that very few people can run uphill and stay below their AeT because it’s so muscularly demanding, so there’s absolutely nothing wrong with walking the uphill sections of a run. Many people who are aerobically deficient also struggle to hike uphill and stay below AeT when they start this kind of training, so it’s also perfectly normal to take short pauses as you hike uphill when your heart rate goes above AeT in order to keep it under control.