A Starting-Point Framework for Training Toward a 5K, Half Marathon, or Marathon, from VO Health's Human Performance Science Team.

This protocol is designed to answer one question first: where are you starting from? Training advice that's right for someone new to cardio can be the wrong advice, or even risky, for someone who already has a base. 

Find your starting point below, then follow the shared training foundation that applies to everyone.

Step 1: Find Your Starting Point

New to Cardio

No running background, largely sedentary or occasional gym-goer.

• Goal: finish → start with a 5K. Give yourself 3 months of running 3 times per week plus a day of cross-training, mostly at a conversational pace. Consistency is by far the most important factor. 

  • A walk-run approach can be very helpful here, such as 30 minutes of 4 min jog / 2 min walk. As the weeks progress, extend the running time progressively until you can comfortably run 30-40 minutes straight. 

  • Utilize trails, treadmills, and cross-training (cycling or stair-master) as needed to limit joint stress.

  • Track your mileage in the background on an app like Strava, but don’t worry too much about the numbers. Focus on time instead, working up to a steady volume of at least 3 hours per week of running/cardio in 3 months.

  •  General points on progression for recreational runners:

    • Avoid a single session running distance that is 10-15% longer than your longest run in the last month. Ex.: If your longest run in the last month was 8 miles, going above ~8.8 miles in a single run may increase injury susceptibility. 

    • Avoid big spikes in weekly mileage that are >20% from the previous week. 

• Goal: perform → All of the same principles written above apply.

  • After 4 weeks of consistency, add in some faster running in the second month:

    • 4-6 x 30 seconds in the middle of an easy run, starting a bit slower and increasing speed with each rep to around your goal 5k pace or faster. Do this 1-2x per week, and increase the number of reps by 2 each week until you get to 10-12 per session. These shouldn’t be all-out efforts where you’re gasping for air, but about 80% effort. Using a hill for these can be effective for running mechanics and strength.

    • Progress the speed work sessions from 30 seconds of running to 1-2 min run / 1-2 min walk at 80-90% effort and extend one of the weekly easy runs to 50-60 minutes.

• Perform 2-3 days of strength training throughout, most easily performed after a run. Simple body weight movements like air squats, lunges, pushups, pull ups, planks, and glute bridges are perfect. Some specific exercises I like for runners are hip airplanes, banded fire hydrants, isometric deep lunge holds, and the 7-way hips series.

Some Base

Regular gym-goer or casual runner already moving a few times a week.

• Goal: finish → 10k or half marathon, 12-16-week build.

  • If you’re not stressing over pace and you simply want to comfortably complete a half-marathon or 10k, the primary focus is gradually progressing volume through increased frequency and duration of your running. Have fun and find some friends to run with.

  • Aim to run 4-5 times per week for 30-60 minutes per run, with most of the time at conversation pace. You’re really just working on accumulating “time on feet” and becoming comfortable with running longer distances. There’s no specific mileage target, but 30-40 miles/week is a ballpark estimate to strive for to make sure you can comfortably handle the distance.

  • At least 1 weekly or bi-weekly run should be a long run. Depending on your experience and pace, about 75-90 minutes, or even up to 2 hours (for the half-marathon) as you approach race day.

• Goal: perform → 10k or half-marathon build, 16 weeks. Introduces some threshold work and interval training.

  • Same points in the above description apply in terms of progression principles.

  • Aim to run 5-6 times per week, or 4-5 days with 1-2 days of cross training (bike, stair-master, rower, etc.).

  • Build the aerobic base with steady incremental increases in mileage over 4 weeks. Stay at a conversational pace the majority of the time, and add some short 10-20 second strides or hill sprints at the end of your runs to practice turning the legs over. Include 1 weekly/bi-weekly long run of 75-90+ min.

  • Begin including 1-2 interval sessions per week. Focus on 2 interval types:

    • Threshold/moderate intensity intervals: repeated bouts of “comfortably hard” running with short rest, such as 3 x 5 min run / 90 sec walk. If 60-90 sec of rest isn’t enough, you went too fast. Over time, increase the length of intervals to 8-10 min and/or number of repetitions gradually to accumulate more time around threshold.

    • Speed focus: Shorter intervals (< 2min), such as 8 x 400m / 2-3 min rest. Progress by increasing the number of reps and/or speed of the repetitions.

  • Aim for roughly 35-45 miles/week depending on experience running and event distance.

• Perform 2-3 days of strength training throughout, most easily performed after a run. Same strategy as the beginner program is fine, but consider 1-2 days in the gym using heavier weight targeting the hips/hamstrings (RDL’s, kettlebell swings), glutes (bulgarian split squats and hip thrusts), and quads (goblet squats).

Regularly Trained

Already has 5K-10K race experience.

• Goal: perform → race-ready build, 16-20 weeks. Half or full marathon.

  • I like a “reverse periodization” approach for longer events (half or full marathon), where you start with speed then shift to more specific training

    • Spend the first ~4 weeks focusing on the 5k, or even the mile, and get a race or two on the calendar. Mileage will be lower with an emphasis on VO2max, speed, and anaerobic development so you enter the 16 week build with a higher speed ceiling. Interval reps should be at 5-10k pace or faster.

  • Transition from speed to endurance through progressive increases in mileage with a heavier focus on tempo and threshold efforts.

  • As a general rule, I like a weekly structure of 2 interval workouts plus a long run. For everything in between, do as much easy/moderate mileage as you can safely handle, per the great marathoner Frank Shorter. Interval workouts should be built around raising lactate threshold:

    • Threshold intervals with short rest (e.g., 4x2km, 8x1km, 4x10min) done at around marathon/half-marathon pace.

    • Speed work (e.g., 15x400m, 8x800m, 10x3min) between 10k-5k pace.

    • Long runs are critical. Build up to 18-22 miles and include race simulations within them such as 3 x 5km at marathon pace or a 3-4 mile pickup at marathon pace towards the end of the run.

  • Doing a 10k and/or half-marathon during your race build is a great way to get comfortable in the race environment and serves as a fitness check.

  • Fueling is key for the marathon, and you need to practice your in-race fueling/hydration plan during long runs to train your gut.

  • Use short strides and hill sprints (~100m) throughout the block to preserve the speed and mechanics you built from the 5k block.

  • Perform 2-3 days of strength training throughout, most easily performed after a run. Same strategy as the beginner program is fine, but consider 1-2 days in the gym using heavier weight targeting the hips/hamstrings (RDL’s, kettlebell swings), glutes (bulgarian split squats and hip thrusts), and quads (goblet squats). It doesn’t need to be fancy or long, keep sessions to ~30min.

Step 2: The Shared Training Foundation

Regardless of which path you're on, every long-term training plan generally moves through the same three phases. What changes is the intensity and volume within each phase depending on your goals, not the structure itself.

Phase 1 — Base Building (~2-3 months) Building an aerobic base is especially important for beginners without a history of running. Stay primarily zones 1-3 (easy and moderate effort) focusing on a steady 10-20% increase in weekly volume until you reach a sustainable training load. It teaches consistency and familiarity with running, plus physical adaptations like: increased blood volume, musculoskeletal tissue tolerance, mitochondrial density, and a bigger, more efficient heart. Skipping or rushing this phase can increase injury susceptibility and limits your ability to handle higher training loads later.

Phase 2 — Add Structure (~1-2 months) Introduce a weekly structure that includes 2 higher intensity workouts per week separated by 2-3 days, like threshold intervals and longer tempo runs. For experienced marathoners, this can be a good time to focus on 1-mile and 5k speed before you shift to high-volume, longer duration, race-specific training.

Phase 3 — Race-specific Build (12-16 weeks) This phase is about specificity and preparing your body for the exact demands of race day. For half or full marathoners, that means a focus on progressive increases in weekly volume with race-specific long runs and threshold workouts as key components. For races 5-10k and below, there’s an increased emphasis on speed, anaerobic development, and VO2max rather than pushing the limits of weekly mileage.

How to Track Progress in Each Phase

If your goal is to finish: RPE and/or heart rate are the only metrics you need. Pick one repeatable workout, a specific route or effort, and track RPE or heart rate against pace over time. You're looking for either a faster pace at the same effort or heart rate, or the same pace at a lower effort or heart rate. Both indicate real adaptation. Adaptation can also simply be seen by observing your training logs and comparing to the previous month or previous year. Faster average paces, more consistent training, and lack of injury all indicate progress.

Heart rate recovery is a useful secondary marker: after a hard interval, note how quickly your heart rate drops at 30 seconds, 60 seconds, and 2 minutes. Faster recovery over time reflects improving parasympathetic tone.

If your goal is to perform: 

• Racing and time-trials. Performance is the best predictor of performance, and doing races of various distances throughout your goal race builds serves a double role as a great training stimulus plus allowing you to build out a speed-duration curve to identify your weaknesses. You can do these alone as time-trials, but its much more enjoyable in a race environment.

• Lactate testing. Run an incremental test at the start of your block (short stages of increasing pace with lactate checks), then repeat every 4 weeks. You're looking for the lactate curve to shift right, meaning lower lactate at a given pace than before.

Some advanced athletes test lactate mid-session during interval work (e.g. checking every 3-4 reps of a set) to confirm they're staying in the intended training zone rather than drifting too hard or too easy. 

Guardrails

• Don't skip phase 1. Base building is unglamorous but it's what everything else is built on.

• More is not always better. General guidelines suggest 150 minutes a week as a floor, not a ceiling, but training loads above roughly 10-12 hours a week for extended periods carry real tradeoffs: cardiac strain, injury risk from exposure, and hormonal disruption from under-fueling.

• Health and performance are related but not the same goal. Decide which one you're actually optimizing for before you commit to a volume level.

• After your race, don't stop entirely. Use the race as feedback for your next block, and if you're sick of your primary sport, switch to something else rather than going to zero. The benefits of training fade once you stop, so the goal is staying in motion!
  
  Want to work with VO Health's Head of Human Performance Dr. Sean Langan, PhD? Check out our Human Performance Lab: https://vohealth.co/human-performance-lab