The measure of heart rate variability (HRV) has become increasingly popular and accessible to many with new wearable device technology. HRV is an individualized metric that can help monitor and track the body’s resilience and ability to manage stress. It's a sought-after indicator for those looking to optimize their overall health, performance, and recovery.

We know that sex hormones fluctuate substantially throughout the menstrual cycle, but are other blood biomarkers influenced by your period, too? Yes—research shows that many blood biomarkers (including those in your iron, lipid, and inflammation groups) can vary substantially according to menstrual cycle phase. And these fluctuations can have important implications when interpreting blood test results. In general, it's best practice to get blood tests done at the same point in your menstrual cycle each time for consistent comparisons.

Using heart rate as a training tool for running is a common practice among runners of all levels and all distances. Like many aspects of health and fitness, heart rate zones and their application in training will vary between each person. Here we’ll dive into what you need to know about running heart rate.

Athletes are always looking for ways to improve performance and take goals to the next level. Efforts for doing just that are often limited to waking hours: nutrition, hydration, recovery protocols, supplement routine and, of course, training itself. And despite all this, research shows that, on average, athletes neglect a critical performance tool: sleep. So how does inadequate sleep affect athletic performance? Interestingly, the oversight of sleep can impact performance, both directly and indirectly, and the effects largely differ by sport.

Resting heart rate (RHR) is the number of times your heart beats per minute (bpm) while at complete rest—measured either when sitting or laying down for a period of several minutes. RHR is a metric that is a useful tool as a predictor of both overall health and fitness level. Here’s everything you need to know about a healthy resting heart rate.

It’s no secret that many athletes or active individuals feel pressure to look a certain way or hit a specific number on the scale. But this mindset can often lead to overtraining or underfueling, both of which are harmful to an individual's mental and physical health. And though the occasional skipped snack or gel won't substantially affect long-term physical health, consistent underfueling, particularly during bouts of intense training, can impact performance, recovery, and overall health in both men and women. Learn the signs and risks associated with underfueling, and the appropriate measures to take to ensure optimal performance.

Chasing big, wild, audacious goals is nothing new to Shalane Flanagan. This four-time Olympian, Olympic silver medalist, TCS New York City Marathon champion, World XC Bronze medalist, American record holder, Nike Bowerman Track Club coach, three-time New York Times best-selling cookbook author, and proud mom inspired runners and non-runners across the globe with her recent incredible running journey known as Project Eclipse.

Spring is here, and that means race season is in full swing; after months of enduring winter training, it's finally time to put your hard work to the test! Whether you're looking for a better result the next time you toe the line, an edge over the competition, or even a shiny new PR, your biomarkers can make all the difference. Here's how some of the key markers we test can help you have your healthiest and strongest race season yet.

As women in the sports and fitness world, sometimes it can feel like we have something to prove — that we can train, grow, and recover with the rest of 'em. But our female physiology isn't a weakness, and it certainly doesn't have to impede our training goals. Just like anything in the natural world, our bodies and hormones go through cycles, which can be monitored and adjusted to accordingly.

Macronutrients or ‘macros’ have become a hot topic in the health and nutrition world, particularly for those looking to lose weight. But the truth is, if you're focused on getting the proper balance of each, it shouldn't be for weight loss, but rather for optimal body function. Here’s how you can use macros to optimize your biomarkers and reach your goals.

Runners and endurance athletes often talk about their personal records (PRs), upcoming races, or the latest fitness tech or gadgets. But there’s always a looming question: How long can I keep going? Physical activity can delay signs of aging by promoting heart health, preventing low bone mass, improving coordination and balance, and lowering the risk of chronic diseases [1]. But endurance athletes also place unique strains on their bodies which can impact healthy aging and their longevity in their sports.

Work, school, and so much of daily life has gone digital as the COVID-19 pandemic forces us to remain home. And though maintaining connectedness with work and play is essential, it’s well-known that all this screen time can have a negative impact on sleep and, ultimately, your wellbeing. Luckily, there are some simple changes we can make to our bedtime routine and desk setup to combat and prevent these negative effects.

Exercise and training routines have many benefits: improved mood, strong muscles and bones, weight management, and reduced risk of chronic diseases, among others. But big training weeks without adequate recovery can negatively impact health and performance, and even your immune system. Here we’ll take a closer look at how training load—or the amount you exercise—can impact your immune system, and what you can do to stay healthy.

Research shows that a healthy gut microbiome can be beneficial for many aspects of overall health, wellness, and longevity. Optimizing gut health can promote immune system health, reduce inflammation, balance hormones, and improve the digestion and absorption of food—all actions that are also important components of being a healthy athlete. So, is there a connection between gut health and performance?

It’s the time of the year again where the days grow shorter as the seasons change. As daylight fades from fall through winter, we’re more susceptible to suffer from seasonal depression, also known as Seasonal Affective Disorder, or S.A.D. According to Mental Health America, up to 5% of the population in the U.S. experiences seasonal depression.[1] But until more recently, the link between nutrition and mental health has been significantly overlooked. Here, we will take a closer look at how our food choices and behaviors can impact our mental health and what actions we can take to use nutrition to help promote good mental health.

The short answer is no, athlete’s should not be focused on eating less or restricting calories before their race but instead aim to maintain their recommended calorie needs throughout the training cycle. This oftentimes feels counterintuitive for many, as you will be training less during the taper phase if done correctly. Here’s why we’re busting this myth:

Having a plan for fueling your body for all the hours you’re spending swimming, biking, and running is key to being a healthy, strong, and happy athlete. While sports nutrition can be overwhelming to navigate it doesn’t have to be. A great place to start building solid nutrition habits is what and when you eat after your training sessions

In endurance sports you’ll often hear athletes talk about different approaches to nutrition and fueling. You may have heard things like ‘training low’ or ‘high-fat, low-carb’ or ‘fasted workouts’. While nutrition is not ‘one-size-fits-all’, a number of the approaches to endurance sports nutrition can be strongly influenced by fads or our current diet culture.

Proper fueling is a key component to being a healthy and strong runner. Whether you’re a student-athlete or lacing up your shoes for your first 5k or marathon, nutrition plays an important role in an individual’s running performance, recovery, and health. Here we will dive into some fueling basics for runners of all levels.

Many athletes and active individuals are looking for an edge to improve performance on race day or at the gym. Physical activity has many well-known health benefits, including promoting heart health, preventing low bone mass and lowering the risk of chronic diseases. Despite this, improving overall health can often be overlooked while striving for athletic goals. With the help of a simple blood test through InsideTracker, you can work to improve your health while still chasing your athletic goals.