We all want to improve our running fitness, but sometimes training relentlessly, without structure, can lead to a plateau in performance. Understanding what we are asking our bodies to do, in order to run faster, provides vital insights into how to vary training for maximum effect. Improving your cardiovascular endurance, also called your cardiorespiratory fitness (CRF), may give you that PB.

Your CRF is how well your circulatory and respiratory systems can supply oxygen to your skeletal muscles during activity. When you improve your CRF, your heart can deliver more oxygen to your muscles as you run, improving times.

The best way of calculating your CRF is through your VO2 max score, which is simply the maximum amount of oxygen your body can utilise during exercise. This can easily be found with a multitude of fitness apps via your smart watch. Following a consistent block of training, some Garmin devices will estimate your VO2 max score. As your training improves, expect this score to go up, although it will be gradual – and some watches give slightly varying scores. The more training you have behind you, the more accurately your VO2 max score will reflect your current fitness.

Your CRF is in your hands; there are plenty of ways you can improve it, and sustain it, within your training week. An improved level of CRF will also positively impact your long-term health. Eddie Fletcher, a sports scientist at Wattbike (wattbike.com), explains:

“The key to success is following a consistent and progressive training plan. You will need to ensure your plan has a well-balanced mix of the following: duration, volume, intensity, rest and recovery.”

How can you do this?

“Variety in what you do is crucial,” says Eddie. “Rather than running the same routes and doing the same sessions over and over, start thinking about how you can mix up your sessions. Include both running on the road and trail sessions, or cross-country races, into the mix. Ensure that the terrain you are running on is also varied, so that you are now doing intervals on flat paths, but also hill work, fartlek on the trials, and including track-specific sessions too.”

Another key factor that is crucial is your BMI, or Body Mass Index. “Aim to achieve a body weight that falls in the healthy range for your age and height,” says Fletcher, “that’s neither too high or too low. As with all training, how you fuel your body and overall attention to ensuring a balanced diet, with good nutrition is important to improving your running fitness.” 

Variety in what you do is crucial...Include both running on the road and trail sessions, or cross-country races, into the mix. 

There are three main elements that you can focus on to improve your CRF:

1. Test yourself before you start

In order to monitor your training progress it’s vital you start with some benchmark statistics. These will tell you where your CRF is now and allow you to track improvements. In your training journal write down what your maximum heart rate (from a sub-max or max test), resting heart rate and running speeds/paces around your appropriate training zones are now. Apps like Garmin Connect and Strava give you a breakdown of these for each run. It’s important when you train to make sure you’re working at the right level, and your heart rate is in the right zone for a specific session. If you are always working too hard, or not hard enough, you won’t progress consistently. Remember, it’s when you rest that adaptations occur.

2. Consistency and moderation are your key words

If you’re in the bad habit of training hard on every run, it will be useful to know that ideally you should keep 70-80 per cent of your training/exercise as low to moderate intensity and duration. Improving and maintaining CRF is about better utilisation of your aerobic system. “Resist the temptation to train ‘hard’ at high intensity too often, as this can have adverse effects,” says Fletcher. “Try a different strategy, by breaking down long runs into shorter durations with shorter rest periods, to improve your physiological response.

“The body needs rest and recovery to adapt and respond at its optimum level to a training stimulus,” he stresses Fletcher. “Less is more when it comes to your CRF.”

Ensure you have at least one or two rest days every week, and have a recovery week, with less intensity and less mileage, at least every four to six weeks. And however good running makes you feel, with its myriad of mental health benefits, if you’re injured or ill, don’t train.

3. Track, measure, retest

It’s imperative that all of your workouts are focused and follow a structure. This means avoiding the temptation to speed up when you’re feeling good, and becoming friends with a slower pace in some sessions. Keep to your training plans, especially when it comes to duration and intensity. Keep an eye on both your heart rate and pace, and be wary of the desire to speed up as a run progresses. Once you have undertaken a block of training of at least three to four weeks, look at your metrics again to see how you have improved. This will also keep your motivation high. “Expect to improve gradually over time,” says Fletcher.

By looking at how your VO2 max has changed, or how your heart rate has come down for a comparable workout, such as a 5K time trial, you can see how your CRF is improving. These statistics are causally linked to the frequency, duration and intensity of exercise. They can also be used to predict times over race distances.

If you’d like to learn more about how to improve your cardio respiratory fitness, visit the Wattbike website, where a number of helpful resources are available: https://wattbike.com/gb/blog/wattbike-crf-health-assessment

The key to success is following a consistent and progressive training plan. You will need to ensure your plan has a well-balanced mix of the following: duration, volume, intensity, rest and recovery.