Body signals: a runner’s heart, low energy availability and ice baths

Some body signals deserve more attention than others. This guide brings together what studies show about the hearts of long-time runners, about low energy when food does not cover training and about ice baths, with questions to bring to your appointment. It does not assess your health: only a professional can do that.

Running and the heart: signs and 6 questions for your appointment

In 284 male athletes around 55 years old, calcium in the heart arteries appeared in 68% of those with the most lifetime training and 43% of those with the least, but among the most trained the plaque was more often purely calcified, a type that may be more stable [1]. In 152 veteran athletes, 60% had normal calcium, similar to non-athletes, although male athletes had more plaques [2].

Over the years, running was associated with a 45% lower risk of cardiovascular death in 55,137 adults [3], and among men with high calcium, the very active did not have higher mortality [4]. Athletes have a 2.46 times higher chance of atrial fibrillation, a type of arrhythmia [5], and among 10.9 million marathon and half-marathon participants there were about 0.54 cardiac arrests per 100,000 [6]. These are observational studies, with many middle-aged men.

• Chest pain, tightness or discomfort.
• Shortness of breath that is unusual for the effort.
• A racing, irregular or skipping heartbeat.
• Dizziness or fainting.
• New, unexplained fatigue.

Any of these signs calls for a check before your next workout. At the appointment, it is worth asking: what is my risk, given age, blood pressure, cholesterol and family history; do these signs call for testing before I continue; does measuring arterial calcium make sense, and what would I do with the result; what changes in my training if it is abnormal; do I need a check before increasing volume or running a long race; and which symptoms should make me stop. Bring notes on your years and hours of training, long races, heart disease in your family and your medications and supplements.

Low energy in runners: signs and questions

Relative energy deficiency in sport, called REDs, happens when food does not cover the cost of training and what the body needs to function [7]. It can be intentional, to change your body, or unnoticed, due to lack of time, appetite changes or a difficult relationship with food, and weight can stay stable even as the body works worse [8].

Carrying extra weight costs energy and time in tests [9][10], but they used weight added externally and short races: they do not show that getting lighter by eating little makes anyone faster. For your appointment, bring 2 weeks of notes on training, sleep and periods and ask: does what I eat cover my training; should we order tests; do I need a bone health check; should I change my training while we investigate; and who else should follow me.

Ice baths: when to go in and when to skip

In 21 men doing 12 weeks of leg strength training, the group that spent 10 minutes in water at about 10 °C after training gained 103 g of front-thigh muscle, versus 309 g in the group that did easy cycling [11]. A cooled leg made less muscle protein than the other over 2 weeks [12], and fast-twitch fibers grew less with cold over 7 weeks, with similar strength [13]. On the other hand, after intense exercise, soreness fell and power improved within 24 hours [14], with the best results at 11 °C to 15 °C for 11 to 15 minutes [15]. A review of 15 reviews rated the certainty as low or very low [16].

Before going in, ask: what is my goal this month; do I have an important effort in the next 24 hours; has this become a habit after every strength session. It is still unknown how long a gap would avoid the effect on muscle, or whether results are the same in women.

How CatLena uses it

On the Training screen, your history of runs and strength workouts is kept with distance, time, sets and calories. In the example below, the week had 2 strength workouts and a 6 km run. This history helps you answer, at your appointment, how many hours and years you have trained; CatLena does not assess heart health or replace your doctor.

When to see a professional