Want to learn new skills or gain insights from industry experts, but have limited space in your schedule? Listen to a podcast. Podcasts are one of the most flexible ways to consume content, and you don't need a lot of extra time. You can listen to them on your daily commute, while you're cooking dinner or doing another everyday task. However, there are thousands of shows out there. How do you know which ones are worth your time?

We've all heard about Serial and everybody knows the classic NPR shows like Fresh Air, but what do the creators of the most popular and engaging podcasts listen to? Since launching The Influencers Podcast, I have met and interviewed some of the top podcasters, so I reached out to them and asked. Here's what they told me:

1. Jordan Harbinger

Jordan's podcast, The Art of Charm, attracts millions of listeners with more than 150,000 downloads per episode. What does he listen to?

Impact Theory With Tom Bilyeu

The show's host Tom Bilyeu is a serial entrepreneur and co-founder of Quest Nutrition. He hosts Impact Theory with a contagious energy and enthusiasm. The show is full of valuable stories of the struggles entrepreneurs face and examples of how they overcame them.

Waking Up With Sam Harris

Harbinger says he tunes in for every episode of the Waking Up podcast. Hosted by Sam Harris, neuroscientist, bestselling author, and philosopher, the show discusses hard-hitting topics ranging from politics to religion. It's definitely not light listening, but it forces you to think about tough questions and see the world from many different perspectives.

Katie Couric

Everyone knows award-winning journalist Katie Couric, but if you haven't tuned in for her podcast, then you're missing out. Every week, a new episode is released and it covers the biggest topics in news, politics and pop culture.

2. Travon Free

You may be familiar with Travon Free (@Travon) from his comedy writing on shows like The Daily Show with Jon Stewart and Trevor Noah, and most recently won his second Emmy for his work on Full Frontal with Samantha Bee.

He's also hosted his own Hamilton-centric podcast with co-host Mike Drucker. Free's top podcast recommendations are:

Still Processing

Hosted by two writers for The New York Times, Wesley Morris and Jenna Wortham, Still Processing is a weekly podcast that covers the biggest topics in our culture. They explore everything from the latest releases in film, TV, and music to the culture of work and dating.

Revisionist History

Revisionist History is a podcast series hosted by renowned journalist and five-time New York Times best-selling author Malcolm Gladwell (Blink, The Tipping Point). The show explores past events and reminds us that there can always be details in history that are misunderstood, overlooked, or forgotten.

BBC World Service: History Hour

The BBC's History Hour podcast is full of intriguing stories and mysteries from the past. Even if you aren't a history buff, the podcast offers valuable lessons from leaders and events that have helped shaped the world today.

Honorable Mentions: Freakonomics, Another Round, and Pod Save America

3. Gretchen Rubin

A true expert in happiness and host of the popular podcast Happier, Gretchen Rubin recommends:

99% Invisible

Design is critical to everything we create, from the latest apps to the newest tech gadgets. In 99% Invisible, host Roman Mars (also the founder of the podcast network Radiotopia) explores all the overlooked details that make a design successful.

Note to Self

How is technology affecting our humanity? The Note to Self podcast, hosted by Manoush Zomorodi, offers a quirky take on what it means to be human in a digital age. For entrepreneurs, it gives a reminder that amid all this impressive tech, the connections we have with real people still matter.

Side Hustle School

These days, it seems everyone is running a side hustle, and if you aren't yet, you should be. Best-selling author Chris Guillebeau (The $100 Startup, The Happiness of Pursuit) hosts Side Hustle School, a daily podcast that explores all the challenges of running a side business.

Everyone that has a day job, but dreams of starting their own venture should give it a listen.

Honorable mentions: Radical Candor, Missing Richard Simmons, Happier in Hollywood (Gretchen's sister podcast), Eliza Starting at 16 (Gretchen's daughter).

4. Lewis Howes

Lewis Howes (@lewishowes) is a professional football player turned entrepreneur and best-selling author. He is the creator of The School of Greatness podcast and book. In his podcast, Howes interviews top business leaders, inspiring celebrities, and other exceptional people on what it means to be great in your career, love, and life in general. These are his top podcast recommendations:

The RobCast

Hosted by pastor, best-selling author and one of Time's 100 Most Influential People in the World, Rob Bell, The RobCast is a weekly podcast. Although a pastor, Bell refreshingly focuses on spiritual growth and what it means to be human today rather than on religious doctrine.

Rich Roll

For anyone interested in overall wellness, the Rich Roll podcast is a must-listen. Guests include notable figures in sports and fitness, entertainment, and business, and it is hosted by ultra-athlete Rich Roll. Each episode explores how you can "unleash your best self" with actionable advice.

Aubrey Marcus

Founder and CEO of the multimillion-dollar nutritional supplements brand Onnit, Aubrey Marcus hosts a weekly podcast that focuses on holistic health. Guests have included the likes of Gary Vaynerchuk and Jamie Foxx, who discuss how to push the limits and support your body and mind.