If you follow Dragons' Den star Sara Davies on Instagram, you'll know she's very into her healthy living routine, regularly sharing her recipes for protein shakes as well as letting fans in on her exercise routine.
Interestingly, just last month, Sara took to social media to share that she has overhauled her exercise regime, elaborating: "I've completely re-thought my whole exercise strategy after learning this one thing about running and fat burning – and it's had SUCH an impact."
Alongside a series of photos, Sara explained: "I found out something about running and fat burning recently that’s completely changed the way I think about my training… If you're running to burn fat and tone up (like me) then your heart rate needs to stay in the 60-70% zone.
"Go above 70% and you're not burning fat anymore; you're burning glucose – straight from your energy reserves."
What Sara is describing here is 'zone 2 training' – ie., keeping your heart rate at zone 2, which can be described as the part of exercise where you can maintain a chat while working out, or as Sara says: "Apparently if you can hold a full conversation while you're running, that's about right."
On how to know if you're in zone 2, she elaborates: "To find your zone: take 220 minus your age. That's your max heart rate. Multiply by 0.7 to get your 70% cap."
Putting it into practice, she says: "For me that's (220-42) = 178 (max). So 70% of that is (178*0.7) = 124.6."
In news that will please runners who don't love speed work, Sara added: "I checked on my Apple Watch… to stay under 70% I was having to run SO SLOWLY… So slowly in fact, I might as well have been walking… so that's exactly what I started doing… just WALKING."
While we know walking is hugely beneficial for our health, Sara shared she wanted to make it a little harder, so she added a weighted vest. "The vest means every step works harder, more calories burnt, more muscle engaged, without me having to run."
She added: "And if you're like me and you're carrying extra weight, walking is so much kinder on your joints than the impact of running."
Sharing how she works out, armed with this new information, Sara wrote: "I still run maybe once a week (because I love it), but I’m also doing two to three fast walking sessions, vest on, heart rate locked in that perfect zone."
She concluded: "Turns out I'm getting fitter and toning up – win win."
Curious whether Sara's new walking workouts are too good to be true, I spoke to fitness professional Sarah Campus for her take, as well as breathwork and running coach Ramonh Ghosh for his input.
"Sara is absolutely right in her post. She explains Zone 2 training so well and how the benefits are incredible," says Sarah, who sings the praises of walking workouts.
"Walking is such an underestimated form of exercise, yet it's accessible to most people and can be made more challenging in so many ways. Walk a little faster, add some hills or, like Sara does here, add a weighted vest.