There’s something tempting and motivating about having a distinct finish line on the horizon. Runners love a good goal to work toward—and a good challenge that helps them get there.
That’s likely why a growing number of programs, training techniques, and events draw in new and seasoned runners who seek adventure. These trendy programs include Jennifer Aniston’s 15x15x15 workout (15 minutes on a stationary bike, elliptical, then treadmill), the 75 Hard challenge, Ironman competitions, and coast-to-coast ultramarathons.
One of the latest to enter the workout chat is exploding on social media: the 4x4x48 challenge. So, we tapped two running experts to catch us up about the pros and cons of 4x4x48, then asked them for a safer, more sustainable way to try it if you’re not quite ready to go all in.
What the 4x4x48 Challenge Is All About
During the COVID-19 pandemic David Goggins, a retired Navy Seal, ultrarunner, endurance athlete, and public speaker came up with the 4x4x48 challenge. As he witnessed races being canceled around the world, Goggins wanted to offer an alternative endurance “event” that individuals could dare themselves to conquer outside of the classic race environment.
To complete a “4x4x48 Goggins Challenge,” which will earn you a T-shirt if you take part in the official program during Goggins’ announced dates (it’s currently on hold, according to his website), athletes must:
- Run 4 miles
- Repeat every 4 hours
- Continue this pattern for 48 hours
All in, a 4x4x48 challenge calls for running 48 miles in 48 hours. For those who aren’t runners, Goggins suggests swapping in another form of cardio (such as swim, bike, or row, for example) for 45 to 60 minutes every four hours.
For some runners, four miles feels like an easy shake-out or a warmup. For others, that’s the longest they’ve ever tackled. Regardless of how much or how often you run, there are some important factors to consider before deciding to attempt a 4x4x48.
The Benefits of the 4x4x48 Challenge
Challenging yourself with high-intensity workouts can be beneficial as part of a well-rounded training program, which should include sufficient rest, recovery, and exercise variety, says Nicole Thompson, ACE-CPT, a San Diego, California-based personal trainer, health coach, group fitness instructor, and medical exercise specialist.
The 4x4x48 challenge is certainly high-intensity and high-frequency. Thompson says that the potential pros for a 4x4x48 challenge include:
Mental Toughness
Successfully completing a task this tough “requires mental strength, discipline, and determination, which can enhance your mental resilience and willpower,” she explains.
Increased Calorie Burn
Running for extended periods at regular intervals can result in significant calorie expenditure. A 150-pound runner can expect to burn around 450 calories during each four-mile stint at a 10-minute-per-mile pace. Over the course of the entire 4x4x48 challenge, this tallies up to 5,400 calories. This is nearly double the 2,900 or so the same person would burn during a four-hour marathon.
Possible Improved Cardiovascular Fitness
“This intense running schedule will challenge your cardiovascular system, which could improve endurance and aerobic capacity,” Thompson says. Although adaptations and improvement typically occur over the course of weeks and months with consistent training—rather than in a mere two days—participants may notice some improvements in cardiovascular capacity after they recover.
Practice in Time Management
Sticking to a strict schedule requires excellent time management skills (and likely, a trustworthy alarm), which can be beneficial in other areas of life, such as work or school.
The Drawbacks of the 4x4x48 Challenge
It’s vital to keep safety top of mind and avoid pushing yourself beyond your limits, Thompson advises, which would only set back your fitness journey—not progress it.
“Honestly, for most runners, the 4x4x48 challenge will have more cons than pros,” believes Erin Beck, NASM-CPT, an Orange County, California-based director of training and experience for STRIDE Fitness. “The structure doesn’t allow your body proper recovery and it requires a high mileage count that the average athlete won’t be ready for.”
According to Thompson, the following are possible drawbacks of the 4x4x48 challenge:
Overtraining and Injury Risk
“The risk of overtraining is high due to the intensity and frequency of the runs, which can lead to fatigue, muscle strains, or other injuries,” Thompson says.
Sleep Disruption
The frequent runs will very likely disturb your usual sleep schedule (unless you normally get less than four hours, which we don’t recommend). In turn, this can affect recovery and overall performance.
Lack of Recovery Time
With only four hours between runs, your body may not have sufficient time to bounce back, increasing the risk of injury and burnout.
Nutritional Challenges
Remember that calorie count we mentioned? Eating and hydrating enough during the 48 hours can be difficult, and inadequate fueling may lead to performance issues or some serious health-harming ripple effects, such as dehydration or forcing your body to use muscle mass rather than energy from the food you eat to power your run. (Don’t miss our complete guide to what happens when runners don’t eat enough.)
“This is an extreme and highly demanding physical challenge,” Thompson says. If you do a 4x4x48 challenge, “it’s not recommended to do this type of run frequently or on a regular basis. Always prioritize your overall health and well-being by consulting with a qualified coach or trainer to ensure the challenge aligns with your fitness goals and capabilities.”
And be sure to run this challenge—or any endurance event—by your doctor to get their thumbs up to ensure it’s a wise choice for your fitness level and overall health, Thompson adds.
Why Sleep Is Such a Limiting Factor in 4x4x48
Sleep is essential not only for optimal performance and recovery, but also for overall health and longevity. A 4x4x48 challenge makes it really tough to get the recommended seven to nine hours of sleep, and the snooze time participants do get is interrupted and fairly likely to be low-quality.
“While doing this type of intense running challenge for two days may not have a long-term impact on overall health and recovery, it can lead to acute sleep deprivation, which can have immediate effects,” Thompson says.
Thompson explains that in just 48 hours, sleep deprivation can:
- Lead to decreased focus, attention and memory; essentially impairing cognitive function
- Compromise coordination and reaction times, increasing the risk of accidents or injuries during the runs
- Raise cortisol levels, affecting the body's ability to handle stress and recover properly
- Weaken the immune system, making you more susceptible to illnesses
- Increase irritability and mood swings, while decreasing emotional resilience (basically, making you not-so-pleasant to be around)
For those who opt into the 4x4x48 challenge, it’s essential to prioritize R&R as much as possible during the breaks between runs.
“Even brief naps and dedicated periods of rest can be beneficial for recovery,” Thompson says. “Then once the challenge is complete, be sure to allow yourself enough time to catch up on sleep and give your body the chance to fully recover.”
Our bodies have a magical way of slowly getting back on track after a night or two of less-than-stellar sleep, Beck says. That said, it’s crucial to not over-tax your system—and carve out time for an extra hour or two of sleep each night—until your body has time to bounce back from the daunting physical (and mental) demands of something like 4x4x48.
A Better Way to Try the 4x4x48 Challenge
For most people, it would be best to avoid attempting this type of run more than once, if at all, Thompson says. Or stick to once or twice per year, max. And exercise caution if you do decide to do it, stopping if you feel aches or pains and prioritizing that recovery.
“It’s more practical and beneficial to focus on a well-rounded and sustainable training program that includes a mix of running, cross-training, rest days, and proper recovery,” Thompson adds.
If you’re really craving a challenge, ante up and give one of these Beck- and Thompson-designed modifications a shot:
→ Beginner: Run 4 miles per day, 4 days per week for 48 weeks. “Over the course of a year, this will help you safely increase your stamina, burn calories, tone your entire body, rack up the miles and support your heart health,” Beck says.
→ Intermediate: Run 4 miles every 12 hours for 48 hours.
→ Advanced: Run 4 miles every 8 hours for 48 hours.
Both of these latter options will allow for a nearly-full night of sleep, plus more recovery time between runs.
Regardless of which path you choose, if you decide to try some form of 4x4x48 challenge, “pay close attention to how your body responds to the challenge. If you feel excessively fatigued, experience persistent pain or notice signs of overtraining, consider cutting back or stopping the challenge,” Thompson says. And if you finished the challenge, make sure to take the next few days off from exercise.
The Bottom Line on 4x4x48
The 4x4x48 challenge is an endurance running event that requires zero qualifier, entry fee or specialized course. It might appeal to the ultramarathoner who’s looking to rack up mileage in a new manner. But running 4 miles every 4 hours for 48 hours is very demanding on the body and brain, so proceed with caution and train your way up to that mileage, rather than just jumping right into it.
It’s also wise to take time to reflect on why you’re feeling called to try the 4x4x48 challenge, if you are. Will running in this way get you closer to your health and fitness goals? Or is seeing pals and athletes on social media creating some FOMO?
“Ask yourself: ‘Is this 4x4x48 something I can do to stay fit for the rest of your life? And is it a healthy approach to fitness for you?’ Your journey has to be sustainable to be successful,” Beck says.
Karla Walsh is a Des Moines, Iowa-based freelance writer, editor, freelance writing coach and level one sommelier who balances her love of food and drink with her passion for fitness (or tries to, at least!). She has over 15 years of professional experience covering food, wine, travel, nutrition, health, fitness, psychology, beauty, relationships and beyond.
