{"id":558892,"date":"2026-02-01T15:28:10","date_gmt":"2026-02-01T15:28:10","guid":{"rendered":"https:\/\/www.europesays.com\/us\/558892\/"},"modified":"2026-02-01T15:28:10","modified_gmt":"2026-02-01T15:28:10","slug":"here-are-the-8-things-that-i-learned-when-i-did-zone-2-cardio-for-an-entire-year-and-how-it-can-help-you","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/558892\/","title":{"rendered":"\u2018Here are the 8 things that I learned when I did zone 2 cardio for an entire year \u2013 and how it can help you\u2019"},"content":{"rendered":"

Counter-intuitive as it may seem, slow running<\/a> is way to run faster over long distances. Easy, conversational pace runs<\/a> can help you to build up your aerobic base and improve your endurance \u2013 without the accompanying injury risk of high-intensity intervals<\/a>. Runner Keltie O\u2019<\/a>Connor<\/a> discovered this for herself when she committed to 180 minutes of zone 2<\/a> cardio every week for a year. <\/p>\n

\u2018Everyone thinks that running is about being in pain,\u2019 she said. \u2018Running as fast as humanly possible till the lactic acid burns your throat. But the slower I ran, the faster I got.\u2019 Putting in the miles at a reduced pace helped her to achieve fitness and personal milestones like completing her first marathon<\/a> and working through grief, while also improving key health markers. Here\u2019s what she learned after 12 months of zone 2 runs<\/a>.<\/p>\n

1. Zone 2 cardio can be the foundation of your training <\/p>\n

As a reminder, zone 2 cardio is activity done at 60 to 75% of your maximum heart rate<\/a>. Out of the five heart rate zones, with zone 1 being very light exercise (walking) and zone 5 being extremely intense (think high-intensity intervals<\/a>), zone 2 is done at a light-to-moderate intensity. \u2018It\u2019s the pace where you can still hold a conversation comfortably,\u2019 says Keltie \u2013 and it\u2019s when you use fat and oxygen as an energy source. <\/p>\n

Slow running requires you to work within zone 2, which, counterintuitively, will help you to run faster long term, as research<\/a> shows it builds mitochondria in the cells, allowing to produce more energy. \u2018Instead of killing yourself and giving 100% every single workout or every single run, you slowly build up your endurance by increasing your volume through a lot of slow-paced runs throughout the week.\u2019<\/p>\n

Although Keltie engaged in a wide variety of exercise styles throughout the year, zone 2 was the cornerstone of her routine. \u2018I did a lot of challenges: the 30,000 step challenge, my run strea<\/a>k, the Berlin Marathon, hybrid training. But throughout that, the one constant was always getting that weekly dose of zone 2.\u2019<\/p>\n

Her aim was to increase her general health and she didn\u2019t have a particular target in mind. \u2018A big focus of mine was Dr Peter Attia\u2019s<\/a> recommendation, which is 180 minutes of zone 2 cardio a week for overall longevity. No specific goals, no races, just try to get two to three runs a week or some kind of cardio where my heart was in that zone.\u2019<\/p>\n

2. Zone 2 is individual-specific and changes day to day<\/p>\n

While a slow running and zone 2 pace often overlap, they aren\u2019t the same speed for a lot of people. \u2018At zone 2, or 60 to 70% of your maximum heart rate<\/a>, normally you can do cardio and speak full sentences. Breathing feels controlled \u2013 that\u2019s slow running. However, some people feel like they\u2019re going easy on a run and will look down at their heart rate on their watch and it is through the roof.\u2019 Conversely, for some very experienced athletes, even a fast run might fall within their zone 2. So heart-rate zones are very specific to the individual.<\/p>\n

A good baseline formula to use for your maximum heart rate is to subtract your age from 220, then calculate your zones from there, Keltie suggests. \u2018But the only accurate way is to go get tested.\u2019 Instead, gauge whether you\u2019re in Zone 2 by the \u2018talk test\u2019: if you can carry out a conversation. Sometimes, she took this literally: \u2018I call my fianc\u00e9 or a friend.\u2019<\/p>\n

She also says the talk test works better than using set numbers. \u2018Your heart rate will change every single day from so many factors aside from how much you\u2019re pushing yourself in a workout. Did you just chug an energy drink with loads of caffeine right before? How much sleep did you get? Did you drink a lot last night? Hormones and other factors will also have an effect.\u2019<\/p>\n

3. Zone 2 training helps you prepare for a marathon<\/p>\n

Zone 2 training helped Keltie build up to her first marathon safely. \u2018Doing relaxed runs made me want to train for a marathon, because I realised, \u201cOh, I can run slow and long, not just short and fast\u201d\u2019 \u2013 so she set herself the goal of running her first marathon<\/a> and being fit enough to enjoy the 26.2 miles. <\/p>\n

\u2018My programme was five to six runs a week, which in the past I would\u2019ve thought was one to three hours every day just lactic-acid building \u2013 that\u2019s what I thought a run was. But then when I looked at the programme, it was mainly zone 2, a little zone 3: slow, comfortable, sustainable.\u2019 While there was some speed work<\/a> and one to two harder runs a week, the pace remained mostly relaxed and conversational. \u2018I was kind of shocked at how you just cruised.\u2019<\/p>\n

Over time, she increased her mileage. \u2018I didn\u2019t just start cranking out 200 km weeks. I started at 12km in a week and then it moved up to 14. Then my long runs went from 10km to 12km. Zone 2 gave my body space to adapt while still getting the volume in to allow my body to run 42 km injury-free.\u2019<\/p>\n

Concentrating on zone 2 paid off, as Keltie successfully completed her first continuous marathon. \u2018I never had to stop. I finished it dancing and smiling on my face \u2013 it felt easy. I left the marathon in a good enough mood that two days afterward I went to Oktoberfest.\u2019<\/p>\n

4. Walking counts as zone 2<\/p>\n

When a medical procedure meant that Keltie couldn\u2019t train for two months during marathon preparation \u2013 so, \u2018no running, no jumping<\/a>, no lifting<\/a>\u2019 \u2013 she had to switch up her approach. \u2018I thought, there\u2019s a different way to do zone 2. Rather than just running, you can also do it walking<\/a>.\u2019<\/p>\n

Things got easier once she\u2019d properly recovered. \u2018Once I was cleared from the doctor, I slowly got back into running. I would run 500m, walk 500m, then do a slow 5km, then a slow 10km, then a slow 20. Instead of forcing it, which I know makes me hate something, I slowly rebuilt my foundation and then signed up for a half and full marathon.\u2019<\/p>\n

5. You\u2019ll see clear health improvements as your body adapts<\/strong><\/p>\n

Keltie showed improvements in several key health indicators. Her blood work results after the medical procedure \u2018came back great\u2019, despite worries that the marathon would wreck her hormones.<\/p>\n

Her resting heart rate also dropped by six beats per minute. \u2018It was about 60 beats per minute in January. By the peak of my zone 2 training, it was averaging about 54 beats per minute.\u2019<\/p>\n

Her heart-rate variability<\/a> (HRV) improved by 10 points. \u2018This is the craziest stat for me because HRV [measures] your stress,\u2019 Keltie reflected. \u2018If your HRV is lower than your average, you\u2019re probably under-recovering \u2013 so you\u2019re not sleeping, or you\u2019re overtraining.\u2019<\/p>\n

But even though Keltie was running more, her HRV improved due to sleeping enough, recovering properly, and not overreaching with her training by slowly adding in volume. \u2018It\u2019s cool to see how my body was able to adapt to more stress because I was doing it at at slow rate versus the opposite \u2013 overtraining and overreaching \u2013 which would\u2019ve caused my average HRV to plummet.\u2019<\/p>\n

Physically, she was able to side step any lasting damage. \u2018Aside from some tweaks and sore muscles, I never got injured once during my marathon training or on marathon day,\u2019 she continued. Keltie also decreased her body\u2019s age by nine years, according to Whoop\u2019s algorithm, which, though not 100% accurate, took into account factors like zone 2, VO2 max, sleep and recovery. <\/p>\n

6. You can\u2019t optimise for everything at once<\/p>\n

Keltie admitted that her zone 5 and strength training<\/a> suffered that year while she concentrated on zone 2. \u2018I focused less on strength training and mobility. I pretty much only lifted enough to avoid injury. The main reason? That\u2019s life. We all only have so many hours in a day and you cannot optimise every single second, especially when a lot of us have desk jobs and our job isn\u2019t being a marathon runner.\u2019<\/p>\n

However, she planned to restore more balance in 2026. \u2018Instead of more miles, I\u2019m thinking of reducing my volume and refocusing on the five pillars of my health span: zone 2 cardio, VO2 max, strength training, mobility and social fun.\u2019<\/p>\n

7. It\u2019s effective for longevity<\/p>\n

At the end of March, Keltie\u2019s dad passed away from heart disease, which changed how she viewed the runs. \u2018Suddenly, this wasn\u2019t just a fun little fitness challenge anymore.\u2019 Further investigation revealed a hereditary risk. \u2018My grandfather on my dad\u2019s side had died of a heart attack. My dad died from a combination of cardiovascular disease and a stroke. And my own blood work had shown not great Apo B (Apolipoprotein B) and Lipoprotein(a) (Lp(a)) [key indicators of heart disease] and cholesterol.\u2019<\/p>\n

She saw that zone 2 work could help her reduce her risk of heart disease. \u2018I realised that even though I\u2019m fit, I\u2019m genetically cursed when it comes to heart disease, which [incidentally] is the number-one killer on Earth. I realised slow running wasn\u2019t a trendy thing that I saw online [but a way to] train for longevity.\u2019 Research has long supported her thoughts, with a study<\/a> finding that moderate-intensity cardio for 150 minutes a week led to blood pressure drops that cut coronary heart disease mortality by 4-9%.<\/p>\n

8. Consistent, small steps make a big difference <\/p>\n

Understandably, Keltie found it hard to stay active initially. \u2018When my dad passed, I stopped training for a little while.\u2019 But then running became her solace \u2013 a way to remind herself that life was still moving in the right direction. \u2018I started something tiny. Even if it was just for a few minutes or a 1km run, I needed a small victory every day in that moment of grief. It wasn\u2019t perfect, but every day I was able to show up and built that momentum. Sometimes a run is all you need.\u2019<\/p>\n

Try our marathon plans for free<\/p>\n

Fancy giving our marathon plans a try? For a limited time only, we\u2019re giving customers the chance to unlock 14 days of free access to our complete training plan library on the Runner\u2019s World UK app.<\/p>\n

UNLOCK ACCESS<\/a><\/p>\n

Related Story<\/p>\n","protected":false},"excerpt":{"rendered":"Counter-intuitive as it may seem, slow running is way to run faster over long distances. Easy, conversational pace…\n","protected":false},"author":3,"featured_media":558893,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[38],"tags":[1199,244240,1201,1198,210,1200,244239,244241,67,132,68],"class_list":["post-558892","post","type-post","status-publish","format-standard","has-post-thumbnail","category-fitness","tag-content-type-default","tag-contentid-474336e6-6d55-4a5b-b0eb-3378b9d1ee95","tag-displaytype-standard-article","tag-fitness","tag-health","tag-locale-gb","tag-shorttitle-here-are-the-8-things-that-i-learned-when-i-did-zone-2-cardio-for-an-entire-year-and-how-it-can-help-you","tag-subsection-motivation","tag-united-states","tag-unitedstates","tag-us"],"share_on_mastodon":{"url":"","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/558892","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=558892"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/558892\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/558893"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=558892"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=558892"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=558892"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}